Typical mastering chain will have 3 main elements:
That's the order I would apply them personally. On EQ, you're just trying to make sure the overall feel of the song suits the genre/mood. Pretty subjective, but a "safe" approach could be a small scoop in the midrange and a high shelf boost for "shimmer" (whatever that means, right?!)
Normal compression allows you to raise the volume of all the quieter parts to be as loud as the loudest parts. Multiband compression lets you do this surgically. For example if you have a rock song with a lot of palm mutes, those spike the bass a ton. So you might compress the low end while letting the highs stay more dynamic.
I've included 1000 words below: