Hybrid webinars play an automated recorded webinar first and then real live one.
Step 1: Go to your webinar editor
Step 2: To run a hybrid webinar, you have to go to "Easy - Webinar Setup" and from "Webinar Type" > select "Hybrid Webinar". Select either Twitch or Youtube Live
Step 3: You will be able to select the video that should play before you go live (1) and also, a backup video in case you do not make it (2)
After setting up your hybrid webinar, please check these articles to learn how to do live webinars
If you want to go live first, then pre-recorded and then go live again, you can do that too. In that case, though, you have to set up your event as "Youtube Live", or "Twitch" Also, this article might help.