How can I use the PSE Addon with the Kodi Remote app on my iPad, because I would like to turn my iPad into a control Center for my HomeCinema. Thanks

I don't think that the Kodi Remote app offers any functionality that is compatible with PreShow, other than the basic remote. It doesn't display program add-ons, which is what PreShow is. It also doesn't load the launcher or skin links, so it unfortunately isn't really compatible with Preshow, or vice versa.

Is there any option how it works with an iPad as a remote for my home cinema? I saw a YouTube video where someone showed something like this.

You can use the Kodi Remote app as an actual remote with PreShow. It just doesn't provide you with any more functionality than an actual remote.

For most situations, you should already have PreShow configured the way you want it prior to using it with a movie. If you are using a skin that has the PreShow, or cinema, button you can use the iPad remote to click that button.