Soundcraft Signature 22 MTK & Reaper on pc

Aguapati

Hello everybody,
I am new in the forum and I don't have much experience using audio processing software.
I would like to start using Soundcraft Signature 22 MTK in order to record music in live as well as in studio applications. Until now I have been using Soundcraft Signature as part of a P.A. system.
I have recently downloaded Reaper on my computer (Windows 10 Professional based) and seted up the ASIO driver. The Soudcraft Signature is connected via an USB cable to the PC, properly configured and recognized as soundcard.
I have created tracks in Reaper and routed them form the desk to the program. I have record-armed tracks and enabled monitoring. The process seems to be working because the signals incoming from the devices pluged in the desk, appear in DAW's interface.
My problem is that I have no sound in the computer's earphone output, so I can not monitor directly from my PC. I have attempted several issues in order to solve this problem, mainly in program's settings but also in the computer sound settings without success.
My question is, if someone can help me: should I forget this option and to try using earphone output directly in the desk? If yes, how can I in a studio application: recording one track after another, using one track as a guide and listening metronome's program, comparing one take to another etc. briefly using DAW's monitoring capabilities with the Soundcraft Signature 22 MTK?
Thanks for your help