More in Bathroom
Remove the cabinet doors and drawers before getting started, to protect them from damage and to keep them out of the way. Instead of removing the roll-down door mechanism, just make sure it was rolled up and out of the way.
Set the first cabinet into the opening. Check the cabinet for plumb and level, adding shims to the bottom and sides as needed.
Drill pilot holes through the side of the cabinets into the studs and attach with cabinet screws.