run a cable from the post-fader aux send of each channel in the board to an input in the card.

Use the channel inserts on the mixer as outputs and take them to the inputs of the Delta. I trust you have one of the Deltas that can be switched to take +4dBu levels. If you want to mix the channels at the same time, you will have to use a loom that has TS jacks (unbalanced) at the sound card end and TRS jacks with the tip wired to the ring at the mixer end so as not to break the sound chain through the mixer.

oh.. because when i put the output of each channel with the inserts i cannot control the amount of sound coming out of the mixer to the program. its just the same level throughout .. i have no mixer control when it comes to volume.

yeah it seems like you are using the pre-fader setting on those outs. this would be usefull if you were using the board for live sound reinforcement and wanted to record separate tracks with levels unaffected by your house mix. from what i see on the description of the mixer online you should have 2 sets of aux sends per channel, one post fader and one switchable from pre to post. so either plug em in to the other send or figure out how to switch the sends you are using.

What I understood from the original post was that you wanted a multitrack recording that you could mix later. If that is the case, you need pre-EQ, pre-fader recording outputs, and that's what the inserts give you.

If, instead, you want a pre-mixed multitrack (why?), then about the only way with that mixer is to use the main stereo outs and as many auxes and group outs as you can. Not very tidy, and difficult to mix on the fly.

the problem is when i go out of the inserts the mics are way too loud and clipping on the recording program.. i wanna have a way i can turn them down or higher them from the mixer.. is that possible?

You haven't said what model of M-Audio Delta interface you have. I would be surprised if you were overloading the inputs if you have them set for +4dBu, but maybe your Delta only has the -10dBm inputs and is not switchable. I know that there is not a lot of headroom on M-Audio gear even on +4dBu inputs, but you should be able to accommodate it by reducing the mic input gain (not the fader) on your mixer.