Find Files and Folders gives you an array of items. Create Folder takes just one folder. The error message is pretty clear. You’re giving it an array of DriveItem when it needs just a single DriveItem.
Well which one from the array do you want, and why are you trying to create a folder that already exists? Doesn’t it being in the array mean it already exists?
Anyway, you reference an array by providing a number after it
output(0) will give you the first item in the array, output(1) will give you the second, etc.