Hi, you should have been followed automatically on Twitch by share2steem upon verifying your account.
After that, it will be automatic, when you start streaming, it will be automatically cross-posted to Steem. Some measures are in place to not cross-post multiple times in case your stream is interrupted, and if you're choosing to archive your videos on Twitch, once your Live is finished, your Steem post will be updated to include the embedded video instead of the embedded Live stream.