Hey! So services vary widely from place to place (since congregations run democratically). The form is based on a traditional protestant service, but with modern adaptations. We sing a lot of songs - I've heard everything from christian hymns to buddhist chants to the Beatles and Peter Meyer (probably not during the same service). We have three hymnals, including one in Spanish.

UUs have seven principles (https://www.uua.org/beliefs/what-we-believe/principles) but none of them require any sort of supernatural belief. Coming from an anti-theist background they were all already things I agreed with. Some people say that you can believe in anything and be a UU, which isn't quite true - any belief system that sees others as "less than", for example, would be incompatible.

As for who does the talking, most congregations have a trained minister (like my partner) who leads most services. They talk on a variety of topics, but mostly about community, justice, activism, and lessons from other religions.

Hope this helps!