Thank you for sharing your question with us.
You can use the Iframe share code to post on social media. First make sure you already have a live stream set up.
Second, select that particular live stream or on demand files and go to publish settings, copy the Facebook share code, and past it on your social media timeline.
For more information you can refer to this link https://www.dacast.com/support/knowledgebase/how-do-i-stream-over-facebook/