Okay, so I'm not sure how surround sound works, but I'd imagine that there's a separate audio track for each speaker. If this is the case, then it's actually fairly easy to set up. All you have to do is set aside 1 mixer track for each speaker in the surround sound set-up, then route the FX channels to each speaker accordingly. To explain a little more in-depth; route your instruments to their own effects slots as usual, then using the little yellow arrows near the bottom of the FX slot, route for example the piano track into whichever speaker track you want it to sound in. Make sure to disable it's routing to the master track, it'll go from the speaker 1 track to the master track. In this way, you can route 1 track to each of the speaker tracks and by using the send amount knobs control the amount going to each speaker. If someone is walking by the screen or something and you want footsteps to fade from front speakers to back, all you need to do is hook up an automation clip (hooked up with the send amount knobs) with one link inverted to do a flawless crossfade between speakers.
This was probably pretty confusing but hopefully you can get started with it, keep in mind i have zero experience with surround sound . When you're done you would just export each speaker seperately and would then need some sort of program to mesh them into a surround sound audio file of some sort.