So your putting a 2.0 into a fiesta, that doesn't have power steering. But the engine has?
If so, you can keep original fiesta alternator mount, just completely take off pump and extra guide pulley, and take off the automatic tensioner. Now do the belt in a triangle shape. (just straight round crank, pump and alt)
Leave top alternator bolt loose, ish, make a braket up to push the alternator out from bottom, so that you can tension belt
crappy pic attached


Alternatively just get a mount which doesn't have PS. I do have one may be selling it., not sure yet.