If you want to use the projectors in Prefabs 17 -22 then please make sure that when you switch on the projector that the source that comes up is LAN (It connects to the WIFI). 

Then on the computer find and open the “Epson iProjection Ver.2.40” (can be found in the start menu in the Epson folder)


Then on the screen that shows up select the Projector for your room for the list ( For example Prefab_17 as shown below)
Click the Join button which will connect the computer to the projector.
The program will also give you a small control bar on the computer which will allow you to pause and blank the screen if needed.