And, Welcome to the forum (welcome for a second time, if you posted in the Introduction subforum!)
I connect my DXR10 with a 1/4" to 1/4" cable, connecting it to Input 2 on the DXR. The XLR channel of my DXR has a low level hiss in the output that I notice if I am playing quietly.
---I send the Main Outputs to FOH. I have the Main Output volume set at -15db, and the control knob in the Output Menu is UNLINKED from the MASTER VOLUME control (see the The Reference Manual, Ouput/Master Section) Doing this allows me to use the Master Volume to turn my monitor up/down without changing the volume of the send to FOH.
For Stereo Monitors, I would configure the Input Source of the Monitor Output to be "Master Left", and the Input Source of the Direct Output to be "Master Right". (in the same chapter of the Reference Manual). I would connect them to the DXRs with two 1/4" cables.
The other way to run in stereo is to use the two Main Outs. If you use the 1/4" outs to the DXRs, you can use the XLR outs to the FOH. Or, you can use the XLR outs to the DXRs, and connect to FOH from the back of the DXRs. The downside to using the Main Outs for both FOH and monitors is that any volume changes to the Main Output of the KPA will also be sent to FOH.
If the FOH is mono, you can connect to the DXRs as above, and use the Monitor Output of the KPA to send the signal to FOH.