Sealing of floor-to-ceiling windows from the outside

We had the area around the floor-to-ceiling windows sealed on the outside with liquid plastic (from the roofer). The window reveals up to about 20cm high, unfortunately no photo. Two coats were necessary. Below that is the basement in WU concrete.

Our terrace should also connect directly and barrier-free to the house or the terrace door. Yesterday I had a first conversation about this. The garden landscaper said that a drainage channel makes sense and that despite the WU basement, at least a stud foil should still be installed here. I will learn more in the coming days.

Bubble wrap is not a seal. It is only a protection for the seal.

Yes, it was 36 degrees and I was thirsty.
Thick coating + noppenbahn, he had said.
Under/next to our terrace is the cellar or we connect to it. The cellar is made of WU concrete. Therefore, I do not know if the above-mentioned solution can be applied universally.
Precisely such transitions are very sensitive.