One the mixer you first have to select the input from the input menu--you should see your audio interface's input options. Of course you should select the input (likely a pre-amp) the mic is connected to. I record the audio into Edison. You want a pretty hot, low-noise signal. Watch out for feedback, the microphone can't get too close to your monitors if they are turned on.
Also watch because I like to set one channel to record on - but if you go back, fiddle with some faders and forget and hit record - you could be recording on the wrong channel which really irks the crap out of me.
But yes. On the far right TOP on the fader rack where it says "none". Click and select your input audio device.
Plug the mic into the input on the interface, set the input buffer to the lowest you can get it within the DAW or the interface's software control panel (64 samples, 128 samples, etc), arm the track to record, press record. Like relic stated you should try and get a decent amount of signal without clipping the input stage of the interface. I usually run mine hitting -10dB peak value and you'd do this by doing a mic check while the track is armed and using the interface gain/trim knob/slider to adjust the input level of the mic. From there it's just recording and after going through and cutting out pops and clicks manually in the resulting wav file.