Since I have researched the subject quite a bit as an amateur, and because I have almost everything for washing and polishing (shampoos, polishes, waxes, pre-wash foams, polishers, etc.), I will share my experience after about 1 year. Initially, I used clay on the whole car even though it was a new one-year-old car—there are always deposits. Then I used 1 step all in one Koch Chemie and then applied this specific wax.
1. You need a small amount, otherwise you'll be rubbing for hours. Also, with a large amount on the sponge, it will get into crevices and letters, etc., and it will "never" come off.
2. Wet the sponge a little before dipping it into the wax, it helps.
3. Many clean microfiber cloths for wiping.
4. As a wax compared to others, it is very good, but as for hydrophobicity, it didn't impress me; what you see in videos is after using a polisher. Just good.
5. As for shine on its own, okay, again I think it's a good wax, nothing extraordinary.
6. The durability is nowhere near "up to" 12 months. For me, at most 3 months with washing 2-3 times a month. At best, it might last 5.
The quantity is enough for many applications.

Basically, it's good to give your car a thorough wash before application and prepare the clear coat. If you don't want to bother with clay or iron remover, you can use a Paint Cleaner.
However, be careful. It should only be a Paint Cleaner, such as Meguiars Paint Cleaner. It should not be a Cleaner Wax or an AIO polishing compound because those also apply a layer of wax, and the Fusso will sit on top of the wax and won't last long.
Just a Paint Cleaner that will clean the surface without adding any protection. Then apply the Fusso. I didn't find the included sponge convenient because it takes up a lot of product and makes application difficult for me.
I found the regular Meguiars sponge more convenient. You don't need a lot of product during application because it will make wiping off more difficult.
If there's excess product left, leave it and when you finish wiping, spray a Quick Detailer on the excess and it will come off. Again, a good Quick Detailer is the Meguiars Quick Detailer.
It gives a very good shine. Excellent hydrophobicity and I will see how long it lasts, which depends a lot on the paint preparation.
It is not for headlights, windshields, or unpainted plastics.

Indeed difficult to apply, also requires a lot of attention to the following:
1. Depending on the prevailing temperature (never in the sun), you must wipe it off quickly, otherwise you will be scrubbing mercilessly afterwards.
2. Like all pastes, be careful with unpainted plastics (use masking tape) because it won't come off at all.
3. Very good preparation beforehand, ideally with clay, otherwise you're working in vain.

It really does have amazing water repellency, but still, when you have a car that has been exposed to rainwater and even worse has done kilometers on the highway in the rain, there is no difference at all compared to before, in terms of how easily it cleans. Do not expect ceramic results, not even one in a million.

Update: an important detail I noticed, if you go to car washes like Lampiko that use hot water, it will leave thin white lines in many places. These are due to the hot water essentially melting the wax you have applied, and it needs to be wiped off with a damp cloth at the end to remove them.
Overall, a bad experience

The product offers amazing hydrophobicity, 1 month after application and it's like the first day. In terms of durability, it promises up to 12 months. However, this will vary depending on use and the frequency of washing your car. On a car that is used daily, exposed to weather conditions 12 hours every day and washed with the application of a gentle wet wax for maintenance every 7-10 days, it started to lose its hydrophobicity, texture, and shine after 2-3 months. Note * It was applied to a Smart Fortwo, that is, almost entirely plastic surfaces and not metal.
Still, it is worth it as it is relatively easy to apply and the amount of product is enough to wax your car at least another 20 times.

Attention, wet and wring out the application sponge well. Apply with straight movements, not circular. And use as little product as possible, 3-4 turns of the applicator in the wax are enough to wax a hood. Do not overdo it, otherwise you will be wiping wax for 2 days and in the worst case you will create haze. Wipe well with a high and soft pile towel (see buffing towels) and you are done.
tip: If you don't want to buy a new sponge every time, then dip the applicator in hot water after use so it doesn't keep wax and dry on it.

Purchased for purely amateur use, I have no previous experience with synthetic waxes. Guided by the company's official YouTube channel, I proceeded to apply it on 2 cars, a BMW X5 and a BMW E92. It was combined with one step polish and I consider the result quite fair for the cost of the product.

Great hydrophobicity (at least the first month after application), incredible shine especially on dark colors, and a huge difference in the temperature of the sheet metal if it remains in the sun for hours.

The process I followed was as follows: good hand washing with quality products (I used CarPro's reset), passing all surfaces with clay purchased from Soft99, washing again to remove any residues left on the surface from the clay, drying and applying the wax. On the sponge that comes with the package, after you have slightly moistened it, make 3-4 light passes over the wax to collect as little product as possible and pass the surfaces of the car with vertical movements. The company recommends wiping the product after 5-10 minutes depending on the conditions, personally with summer night application in a closed garage even in 5 minutes the wax did not come off as easily as I expected, nevertheless with a little patience and with 2 clean microfiber cloths you can remove all the product after a few minutes.

The difference is very noticeable on the treated surfaces from the first minutes after wiping, so slowly and with small areas each time a car is completed in about 1:30 hours depending on its size of course.

Satisfied with the purchase, the package has plenty of product that is definitely enough to treat 10 medium-sized cars, we will see the durability over time. A very user-friendly synthetic wax with excellent reviews even from the biggest detailers abroad!!

The car (Renault Clio) is relatively new and its color is in perfect condition. I simply want to use it more for protection.

Instructions:

1) Wash the car well
2) Wipe it with a dry cloth to remove all water
3) Place the car in the shade, the process should not be done under the sun
4) Take the sponge from the package and dip it in clean water. Squeeze it and put it in the wax, do not press it, just twist it 2-3 times right and left.
5) Apply the wax on the car, do not make circular motions when applying it with the sponge, only up and down and right and left.
6) Let it dry for about 5-7 minutes
7) Rub it with a dry cloth, where it leaves no residue. You should rub it gently until all the wax is removed from it.
8) When you finish, leave the car in the shade for 2-3 hours.

Result, impeccable. Those who see it tell me which car wash I have taken it to :P

If you have aluminum rims, you can of course apply wax there, using the same process. Just be careful, wash the rims well, do not have brake dust.

If you have a new car, it will make it look like you bought it 5 minutes ago. If you have an older one, it will remind you of how it was when you bought it. Overall very satisfied, now let's see how long it will last!

First of all, let me say that I am an amateur and it is the first time I apply a coating on a car as I have never used wax before. Secondly, if you think that you get the fusso, apply it, wipe it off and the car becomes brand new, you will be very unpleasantly surprised. What they conveniently hide from you is that before applying it, you need to go through 4-5 stages of cleaning the car with other products that cost twice as much as this one (70 euros+) and of course, a lot of effort and dedication. For those who are still determined, watch the relevant videos of the company and others on YouTube, so that you know how to do it and be prepared to dedicate a whole day if you want to do it correctly. The final application of the fusso is easy and the packaging is enough for 20-25 times (as they say and it seemed true to me since you use very little), so it is cheap per application. I really liked the result and it is extremely hydrophobic, making subsequent washes much easier! The only thing that has not been tested is its durability, but they say that if you wash the car properly, the protection will last at least 9 months. If you are willing, I highly recommend it!
Update 1 year later. The coating indeed lasted for more than 9 months and I will apply it again. Very satisfied with the product!