It can be intimidating, but I've learned that it's all much easier than it looks. You can't learn if you don't try so go for it! We are here to help.
Circular stitch markers go ON the needles to mark a stitch before or after it. Sometimes you might have two with a stitch in the center. They are used to denote that you'll be doing something like an increase or decrease or they can be used to just mark a certain number of stitches.
I'm glad you've watched the videos. Here's some more help that is just photos if you need to see it that way, too.
Here's a hat video -