like you say it would seem it’s just a question of getting the outputs configured correctly
assuming you have the full version of C5 with Control Room, try this set up:
go to devices> vst connections.
In the Outputs tab - disable the stereo out buss by changing the box in the audio device column where it lists your Presonus device to “not selected”
in the Studio tab: Create a new stereo monitor bus(add buss-monitor-stereo).In the audio device colum for this new monitor buss, select Presonus. In the device port column select the ports that you have already been using, ie the ones your speakers are connected to!
Open the Control Room mixer(devices menu) and make sure CR output is activated - (assign button next to the fader will be lit blue)
That should work!
By Outputting through the control room you have a few advantages-
You’ll be able to audition your loops in Media Bay!
You’ll be able to set up independant Cue mixes (confusingly called studio sends) for any musicians or vocalists.
You’ll be able to adjust the level of your monitor speakers via the the control room mixer, check mixes when summed to mono, use the “listen” function, etc.
You can leave the main output fader on the mixer for sorting mix levels rather than having to use it for sorting monitor volume.
Hope that helps. Its a PITA getting used to new kit.