Hi Annie,
My understanding is that you can just download Brave, it's a standalone browser and you don't need to have Chrome installed first. Just
go here and download for Mac or PC. I can't find anything that says you need to have Chrome first, and I can't think of any reason why you'd need to. If you've found something that says otherwise I'd be interested to see it. Maybe you've read that Brave is based on Chrome (or at least, on Chromium, which Chrome is also based on -- as is Microsoft Edge and various other browsers)?
Matt