Questions from a mod newbie

I am the mod for two communities, one I created and one I was added. I don’t see where I can edit the sidebar, etc. I can edit and delete posts, and when editing I can pin a post. This is on Edge for windows (work computer) and safari at home and iPhone. Is there something extra I need to download? I am (clearly) not a programmer, just trying to do my part for the greater good. 😁. I also can’t save my Matrix ID on my profile, keep getting error about my language choice. @zerlyna:matrix.org. Thanks!!