Usually it will be opened & closed by the ground personel( Engineer or Technision) but in some remote cases can be done by the cabin crew from inside.
To Open the stair you don't need hyd. sys. once it's unlocked, it will open and unfoleds by it's own wight and design, however for closing you do need a hyd. sys. (normal way). But if for some reason there is no hyd. sys. or malfunction in the retracting sys. it can be folded and closed manually.
Hope I could answered your question.
Fixitor...
