Multi meaning left and right or multi meaning more than 2?

If you want to record multi tracks where you mean laying track upon track upon track, we'd need to know more.

Is what you are doing recording a band in the room with everything running through your mixer and you want it to record on individual tracks?

Do you have a credit card with a lot of room on it, because you are now talking about multi track capable hardware. Somewhere in the bowels of these forums you will find a thread about my experiene with Mark of the Unicorn hardware. That would required a fairly expensive interface card for your computer (I think it cost me like $175 used) amd a couple of hardware interfaces (MOTUs were fine for me, but the will do only 8 tracks of analog audio each, so you'll need at least 2. $85-ish used on Craigslist or eBay.) And a bunch of patch cables, one per channel. Then some kind of DAW software that will record multitrack input, unless you play in perfect tune, time and balance on the first take. If you just record those many tracks mixed down to one left and one right into Audacity, you are cool with just Audacity running and you can mix the levels at the mixer. If you want to do any dubbing, redos of a section, etc... remember that with just a L and a R you have no control over just the bass, just the piano, just the guitar.... everything is ganged together.