How to turn on cable?

In my room, I have 2 cable plug (thingys, the ones where you can plug in your phone or the TV box). I want to hook my TV box up to my projector. I hooked it up and everything, and It was working, but it said "Complete Signal Loss". My TV is on the right side of my room, and I want to plug it in on the left. My parents say that that cable, plug thing, isn't "activated" on that side of my room. But my dad said "There's a big bow downstairs with that kind of stuff in it but I have no clue what to do with it." So how to I "activate" that box without having a cable guy come out and do it for us?