I finally managed to do this script almost what i want:
it is listing the subfolders of a folder-name that i put in A1

But instead of having the result in Collumn B BELOW each other, i
would like to have it
next to each other, into 1 cell (in this case, B1), seperated by
comma.

Example: A1="Folder" B1="Subfolder1,Subfolder2,Subfolder3"

Sub tt()
Dim FSO, FO, FU, F
Set FSO = CreateObject("Scripting.FileSystemObject")
Set FO = FSO.GetFolder(ActiveWorkbook.Path & "/" & Range("A1"))
Set FU = FO.SubFolders
For Each F In FU
Range("B65536").End(xlUp).Offset(1, 0).Value = Right(F, Len(F) -
InStrRev(F, "\"))
Next F
End Sub

PS: i dont need to go to a deeper level of subfolders (dont need to
see what folders are in, e.g. subfolder1)