i dont get it 2

seriously. how do i use this? can this be used to sync appdata across 5 pc’s?

Please check the Documentation at https://docs.syncthing.net and read it thoroughly, especially the Introduction.

However, if you mean the AppData folder in Windows, then most likely no, because those are mainly settings of the installed software and the operating system itself. You could possibly sync some of them selectively, but trying to sync the whole folder will likely lead to some disastrous consequences.