how to manage this system???? advice please

[nocaster]

Hi,
I've bought a Delta66 card (4 in/4out +spdif), and a Behringer Mixer UB1204fxpro.
I do not have a cuple of monito to listen, so I use my old HIFI (Pioneer amp and Bose speakers).
Some questioons:

1- listening: should I go from Delta output to mixer in input1 or should I go to 1&2 from delta out 1&2, respectively?
and: from mixer, I'm going out from aux sends (jack-type) to couple of rca in the amp (line). It's working, but I'm wondering if it is the best connection!!!

2- recording:
I normally use guitars and voice and Alesis Sr16 out to go into INPUT 1-2-3-4 of my Delta card.
For mic and guitars I go before in my Joe Meek comp (Mq1), then from it to Delta. (Ipm not using my mixer preamp).
Is it correct?

I've some confuzion about how to use tjhe mixer in and out, and about MONO and stereo, could someone clearify or link me??
thanks
NOK