To record in stereo you have to have the tracks panned left and right, bus 1/2 pressed for both tracks 1 and 2, and the 1/2 bus slider up (to between 7 and 8 like usual).
If you run it with the pans centred you will record both input tracks on both tape tracks (in other words, two identical tracks of mixed mono).
The panning l/r (odd/even) assigns each mixer channel to a bus channel:
If you've got bus 1/2 pressed, panning to 'odd' (or 'left') will send that channel to either track 1 or track 5 (whichever is armed). Panning it to the 'even' (or 'right') will send it to either track 2 or 6.
Likewise, if you've got it punched to 3/4, 'odd' will send (route) the signal to either track 3 or 7, and 'even' will send it to either 4 or 8.
This way, using the built-in bussing, you can send any track from the mixer to any track on the tape, and therefore mix several mixer inputs to a single or multiple tracks on tape.
Anyway. Hope that was clear enough. Bussing can be a bit weird to wrap your brain around, I know.
D.