Hey @ma1neevent it's pretty simple.
For voting you need to have steem account - that is the only prerequisite.
If you're on steem you can login to dlive with your credentials. It's exactly the same as with Dtube, Dsound and Dmania. I personally use active key because posting key won't work for Dlive (not sure if it's the same for other three).

People watching your stream can vote on dlive or they can vote for that post using steemit.com or busy.org. It's up to them. If you're following someone and have automatic vote set, for lets say 30 min, it will automatically vote after that time.

You can chat as well when streaming - but it's a bit buggy and there is few second lag for now. All the chat is turned into comments for that post (if you change the comment - the line in chat will change as well). I've found out that one because I made a typo and I tried to correct it.

That is all I know so far. More testing is needed by my side.
I hope it helps.