How Can I Set a Default Region and Realm for a Channel?

If your channel topics starts with text like:

region/realm

The bot will use that as a default (if the user does not have their own defaults set up)

So, if your topic is  us/malganis and member can run a sim without including the region and realm.

If you want to have additional information in your topic and have the bot defaults, add a comma after the region/realm:

us/malganis, This channel is for Raidbots sims