Please help! audio setting issue with AG06 yamaha mixing console

Im very new to cubase and bought ag06 mixer to plug mic and guitar,
i’ve installed all the drivers and ran the software,

when i use headphones from my computer driver all is well , midi keyboard works ,i can hear samples in cubase and playback and hear what i recorded,

The problem starts when i try to use my ag06 mixer and i switch the settings in cubase to get input from the mixer , and give output to the stereo of the mixer which is the only option for output.
i plug my headphones to the mixer and can hear the guitar and the mice but cubase output doesn’t work , cant hear any thing i recorded or any samples, no sound at all.

i can see that cubase recognize my guitar and mic input by the volume levels going up when i play and i can even record it and switch back to computer driver and listen from computer speakers, but i’m recording with no background track or sound. i believe its not the way its done.
why cant i hear cubase threw the mixer? is there any special setting i need to do beyond selecting driver and bus?
can the mixer give output from the computer at all?
please any idea would be great i’m lost on advice!
many thanks