You may find some install instructions in the Support area of X10.com. I have seen them there.
Wireless or wired cameras?
Do you have any software and an interface to send the signals to the cameras to switch if wireless?
Only one wireless camera can be on at one time as they interfere with each other if more than one is on at a time. They work in groups of 4 1-4;5-8;9-12 and 13-16. All on one house code. The wireless cameras have an addressable power supply with address dials. If you turn on; lets say B2; cameras on B1, B3 and B4 automattically turn off.