The first interface that looks like a side panel is what we call the "Candy Bar." The Candy Bar is where you access your current rooms, create new rooms, and send direct messages. This lets you quickly jump between rooms at any point while on Here and provides greater visibility to what rooms your friends are in.
From the Candy Bar, you can also access your profile and update any of that information like your name, username, bio, and pronouns. For those of us that like to have a tidy desktop, you can close out of the Candy Bar while in a room and your room will stay open.