You use the "studio" for your channel. It'd be nice if you had another computer or someone to manage the overlays for you otherwise they'll just see you turning on the overlays in the stupid java crap they call "studio"in livestream.
I remember doing a lot of work on mapster's old channel, might wanna check that out. Also overlays look disgusting, love them :P
If you ever need someone to do some graphic casts contact me ;o
You can do all sorts of stuff btw, know how TV channels have their logo up there in the screen? You can do that. It's on the branding tab, it's called "bug" for some reason. You can do text marquees on the bottom of the screen just like some news channels, display random text so people can remember what they're watching, and such.