Ok, yeah, looks like you figured it out. You can drag and drop across your bookmark bar if you have it enabled. Otherwise can create a bunch of folders or different places within bookmarks. Whatever order you place Bookmarks is the way they appear. I do believe by default it will put new bookmarks on the bottom of the list.
Also, when you keep talking about your Firefox bookmarks, I’m not registering that. If you’re saying it’s a folder named “Firefox” or whatever from you importing over, then that’s going to be a separate folder I do believe. You’d have to drag those out of it and place it in Bookmark folder or something of the sort to have them appear on your Bookmarks. Sorry, I’m very bad at explaining, especially when I’m not picturing exactly what a person is saying.
In any case, I think you’re saying you’ve got it figure out. It’s nothing difficult.
Btw, since you’re new to Brave, it might help to check out my little FAQ I wrote a while ago. It tackles some of the more common issues people have posted about here on Brave Community, as well as come common knowledge/info.