For product specific questions you may do better in the specific product forum
To find Muse, start at the Forums Index http://forums.adobe.com/index.jspa
You will be able to select a forum for the specific Adobe product(s) you use
Click the "down arrow" symbol on the right to open the drop down list and scroll
What exactly you are referring by share code to social widgets Muse ?
If you want to use your own Youtube videos then you can just add the video ID to youtube widget control.
In case you want to embed youtube video directly to Muse page without using social widget , you can copy the share embed code and insert on page using Object > Insert HTML.