HOW DO I BLOCK POP UP ADDS?

In Firefox, go to Settings → Privacy & Security → Permissions and make sure Block pop-up windows is checked.

For regular web ads, Firefox’s Enhanced Tracking Protection can block a lot of the tracking behind them. Set it to Strict under Privacy & Security if you want stronger blocking.

If you’re still getting ads after that, tell us whether they appear as new windows/tabs, notifications, or ads inside the webpage. Those are blocked in different ways.

Are these as small popups on bottom right corner of Firefox window?. If so then these are likely just web push notifications from sites you have allowed to send you notifications. You can revoke the sites as shown in https://support.mozilla.org/en-US/kb/push-notifications-firefox

Are these as popups opening in new tabs or new small windows or such while on some websites?. Then perhaps a ad blocker related extension like "uBlock Origin" among others may help. https://addons.mozilla.org/firefox/addon/ublock-origin/

Maybe you changed your popup blocker settings in Firefox. https://support.mozilla.org/en-US/kb/pop-blocker-settings-exceptions-troubleshooting