I would take a class not online and do ALL THE HOMEWORK until you understand everything for learning Microsoft Office applications. I took it a brick and mortar, it was in a lab and you can do most of your work there usually.
I had to take that as part of curriculum a long time ago, and I learned how powerful EXCEL really is, not that I need or use much of any of it, but still, it was interesting. All students had to take it because all classwork was required in Office so everyone was expected to fully utilize Office all through school
Online learning basically sucks. It puts ALL the work on you. It's nice to have an instructor or Prof around for questions and such if you need it, I didn't but you might, plus you can follow along on a pc with the instructor for hands on.
students get a big discount on Office too so you can put it on your PC and use it for homework and such