Setting up a lactation room (Breastfeeding Room) is easy if you have a space available. The main requirement is a space big enough to accommodate basic items for one or more breastfeeding or breast pumping mothers (breast pumping or breastfeeding). The room must be shielded from public view (meaning door must be lockable and any windows must have curtains or blinds). Here's a basic shortlist to follow.
Outlet to connect electric breast pump
Sink for cleaning nursing equipment
If you can't provide a sink inside the lactation room, you should at least have an alternate space nearby with a sink and running water such as women's restroom for mothers to clean their equipment after expressing breast milk.