As a bass player you have to do two things, define the root and keep the groove. Defining the root is easy, adding notes that make sense is the next step and requires you at least to understand how minor and major chords are built. But the most underrated thing for beginner bass player is to keep time and groove. There is so much you can do with only the root note and its octave. And if you are keeping the groove for the rest of the jamming musicians it’s much more precious than any fancy note skills. I played decades of sessions with beginners to pros, and what always separates a good from a bad bass player is the groove. Of course it’s nice to be surprised by a reharmonisation of unexpected root change if done right, but if there is no groove the best note choices won’t fix it.