I have trouble playing bass and differentiating between minor and major. I guess I have a lot more questions, but essentially I am confused as to how I can play in minor.

Last but not least, if a song is in G, and the progression is G, C, Am, G, when I get to the Am, after I hit the root note, if I wanted to play more notes to fill in, would I play notes in an A minor scale? If I would, then are their certain notes that I would have to play to transition back to G?

I'm sorry if I am confusing but I have taught myself everything I know by ear and by myself ever since I picked up my bass, and I find it a shame that I can learn so many songs but not understand or apply the easiest concepts. Thank you guys for helping and your patience with me.