You need to get creative, you little wanker.
Your 802a, if its anything like the one in my kitchen...hes NO inserts, so scratch that idea.
HOWEVER... it does have TWO aux sends, (one pre, one post) and two main busses.... Giving you THREE discreet channels.. . plus a postfader boosy.
SO YOU DO THIS:
Get your little band together. . . say, git, keys, vocals, drums and skinflute....setup your bedroom studio like so:
Drums in the corner... get your old wrestling mat out, drape it with towels and make a little partition to sheild the drummer from unwanted government rays...
Keys and guitar facing him... only with thier amps in a DIFFEWENT WOOM. no bleeding..
crank all your panpots to the left, and your levels up alittle. The LEFT will be your slop channel... or GUIDE TRACK... so when you overdub your git, keys, flutes, and vox... you will know where they go... since you sure arent counting it out.
So... run a patch from your LEFT main out to your input #4. GUIDE TRACK...everything goes in it... but youll erase it eventually.
Run your guitar LINE OUT into 8
KEYS into 7
STEREO SHINFLUTE into 5-6.
SLOP VOCALS into 4.
ensure that on these channels the AUX SENDS are at MINUS INFINITY and you are cranked to the left.
OK.
NOW... put your crappy peavy mic in the kick drum. Run it to channel 3. Crank its pan pot most of the way to the right. Patch RIGHT main out to input #3. good times. Ensure both auxes are at MINUS INFINITY. Thi8s is your KICK DRUM track.
get your crappy 57 knockoffs up in the most bomber overhead array you can. Run the one on the RIGHT into channel #2. Pop AUX #2 up halfway-ish. Run your AUX 2 SEND into input #2. this is RIGHT OVERHEAD.
Run your LEFT OVERHEAD into channel 1, and pop Aux 1 up a little bit... run AUX1 SEND to input #1. youguessedit...LEFT OVERHEAD.
Dial in your levels and you are ready to ROCK AND ROLL!!!
xoxo
PS.. there are other solutions if you have say.... a pair of akgc1000s and some 9-volts, or whatever. Tell us what you have and what you want to do, and we will chuckle.