Congrats on the G3X!
Given that you're new to multi-effects; you'll have so much fun just exploring different fx & amps, and seeing what different parameters do to change the sound.
I think the most "effective" modules for bass will probably be the modulation effects like Chorus, Tremolo, Flanger, Phaser, and others. However, just be aware of how much they affect your low end. Hopefully using the wet/dry mix, you can make sure there is enough dry signal to keep your low-end frequencies intact.
When it comes to overdrive, distortion, fuzz; there are no wrong answers -- or no right answers

It's such a matter of personal taste. I don't use those kinds of effects for bass very often; but for me, I usually try to make it break up more when I'm playing louder, and I try to use whatever available controls there are to roll off the high end to make it a bit darker.
The envelope filters and synth stuff may or may not respond well to bass, but by all means get in there. That's some real fun.
As compressors go, the G3 is of an age/generation where Zoom's compressors just aren't fast enough to be useful for bass (IMHO). They are especially too slow for slap bass. By all means, you should still have a play with them, you'll get a good feel for smashing the sound, it's just that you won't really learn much about the real ones by playing with these fake ones, because they just aren't snappy (responding quickly to hard attacks) in any meaningful way. Later Zoom units; B2 Four & MS-60B+ have improved this greatly.
The reverbs and delays in the G3 are pretty good, and you can use them to create a big ambient wash-- which is satisfying and fun.
On a final note, depending on the kinds of gigs you get, if you are trying to create an appropriate sound for a particular genre of music, then you'll have to be a bit careful about your choices and settings. If you're just hanging out and trying stuff in jams or at home, then go nuts. You really can create your own kind of signature sounds with that box. However, I must caution you, now that you have drunk from that well, your thirst shall never be slaked. Your hunger will grow and soon you will have a second multi-effect...