!lemmy_support@lemmy.ml seems overall pretty technical, but I've seen people post asking about how to use the site in general. There might be other communities as well.

lemmy@lemmy.ml is probably your best bet since I think that's the community about Lemmy on the instance run by the Lemmy devs. lemmy_support@lemmy.ml is another option but might be more about running an instance, though I'm not positive.

All the major lemmy instances usually have a community dedicated to answering questions about lemmy. I'd suggest you to check out https://lemmy.world/c/support since your home instance is lemmy.world

The "chat" community on most instances is another good rec, especially on the midsized ones. Like people ask Lemmy how-to or recommendation questions all the time. Neat as I can tell they're mostly a catch all for conversations, so questions get asked a lot too.