Okay, to be clear, there are several ways of working. Traditionally, you'd record all the tracks of your song onto the multitrack, and then mix that down to a 2-track tape deck. This would then be the master - you'd make copies of that to send to the duplicators the record company or whatever you were doing with it.
If you have 8 tracks or more that works quite well for most material. With 4 tracks it's a bit of a problem, unless you're only tracking four mono instruments or less. What they did in the sixties before 8-track became available much, was they recorded four tracks, mixed them to one or two tracks on a second machine, and then recorded a few more tracks, mixed it back to a track or two on the first machine and so on. This gives you a fair bit of generation loss and it's a real hassle, but it can be done. (It's why I started with 8 tracks as a minimum, I knew what four tracks would entail and it wasn't suitable for the kind of music I'm doing)
What people do more recently is track to tape, and then dump the tracks into a DAW and mix in that. Personally I'm not fond of that approach, it feels like cheating to me (and this is coming from someone who arranges and composes all their music on a computer*) but people do it.
Advantages are that you have less generation loss, you can reuse the tape after dumping to DAW and so forth.
Disadvantages are that you're essentially recording to the DAW anyway (the limitations of tape can be helpful sometimes), and you'll have a hard time lining the tracks up again later as there will be timing drift.
Some people track to DAW through the tape machine, by putting all the tracks into record, and sending the output from the playback head into the DAW. That's supposedly a cheap way to get a 'tape' sound for the price of a 1/15 second delay. It will only work on decks with three heads (The R8 and
the TSR-8 don't), the 22-4 might.
* In some ways I like the extra work involved in tracking and mixing to tape because if the entire thing was done from start to finish in software, I wouldn't feel like I'd accomplished anything.