What mics are you using? If they need a phantom power, there is no way they will work without it. When you plug in XLR and switch phantom on, it should show the "Mic" light on the unit (I suppose you are using Arturia AudioFuse). Then open Arturia Control Center with the "A" buton on the unit pushing it once, then wait.
There you can see if something is coming in. Also on the unit VU metter too.
Next, check if you are sending to the correct speaker output (Speaker A or B). Then you have a MIX rolling button on top right on the unit, turn it to "Direct" to monitor the direct signal and see if you can get it through the speakers. If you can, the rest is a software or routing issue, but you have to make sure first which is it to get further ideas on helping you.