There are multiple possibilities:
1. check if your rough-in working properly - this can be easily checked using loop-back test. You can "short-circuit" the rough-in red and black connectors using a copper wire, and test the other end of the rough-in using a ohm meter. It should show short circuit.
2. check if your amplifier/receiver supports multi-room capability. If so, then connection is easy - just connect the cables to the secondary ports. However, you still need to make sure the receiver is playing the music in the mode that sends sound to the speakers you connected (for example, if in stereo mode, you would connect to main Left and Right, not the surround-left and surround-right).
3. if your amplifier/receiver does not support multi-room, this configuration can be problematic, because you would have to sacrifice one of your surrounding ports for second room. When you play music (typically default in stereo), depends on which mode you play, it can be on left and right speakers only, or all speakers if you choose pro logic, simulated or stadium. However, your main room surrounding will not work in the most ideal case.