What does that mean at epic games?

I want to install fortnite and it says so.

There you choose the storage you want to install it on. It is best to take the storage that is the largest. You can see that in Explorer under "This PC". For me the biggest path is D. So change your C: to D: because C is probably your faster hard drive.

P.S.

Of course you have to have enough space and put it in an empty folder so that the game can be installed.

Ne doesn't help me

What happens if you do everything as described?

So it says that your directory must be empty. This means that nothing should be where you install it except at most an EMPTY folder. If that doesn't help either, unfortunately I can't help you and in addition, your hard drive (e.g. D. Must be specified in both lines (i.e. Folder and file path) so that everything matches

I have enough space