When you install Firefox on a desktop/laptop, it promotes the idea of having your Firefox data synchronized between Firefox on your computer and Firefox on your mobile device, but it's completely optional. If you're not interested, just browse away from that page. As for -- <blockquote> I don't want the phone to become all cluttered, and I don't want it reminding me about everything unless I ask it to. What do I do? </blockquote> -- you may want to find a site where people are more familiar with your particular device and can advise on how to adjust its settings to meet your needs. For Android, I've often used this one: https://www.androidcentral.com/. In addition to news and tips, they have forums for lots of specific devices.