I am new to Studio One, and new to StudioLive 32SC. My history with music software and equipment was you plugged it in, plugged in the speakers, and everything generally worked (save a few drivers). With Studio One you actually have to physically route where the sound goes. What's more confusing, from what I can tell, you have to have a song open to get where you need to go (I'm writing this comment for Studio One 4.5 btw).
With any song open, blank should work, go to "Studio One", then "Options." On the bottom left you should see "Song Setup." Open, click on the "Audio I/O Setup" at the top. Here is where you route the inputs and outputs of Studio One (should see two small tabs just below the main bar). If you click on the Outputs, there is one "Main" output that is going to Channel 1 and 2.
I'm still quite new to StudioLive 32SC and may discover that my comments here are wrong or outdated as I learn more, but I did get it to work. My situation was I could hear everything, instruments plugged in, the computer, etc. but I could not hear what was coming out of Studio One. The meters were moving, no sound. No headphones, no monitor, etc. It turns out the default channels to the main outs in StudioLive were 37 and 38. So if you go back to Studio One and change that "Main" output to Channels 37 and 38 (if you click on one channel both should fill in the stereo output), that worked for me. I'm sure there is more to understand with configurations, etc., but definitely feels like they just "assume" you understand all of this as the directions give no clear indication on how this is supposed to work, at least not in any "Quick Start" guide. This was buried in instructions and online help. Really need some audio routing instructions for beginners with this equipment. Hopefully helpful, good luck.