I’m starting with a Team Site template and I’m going to use the “Edit” icon in the top right to put the page in edit mode.
Select “Page” from the ribbon and choose “Insert” then “Web Part”.
Select the Script Editor web part under “Media and Content”.
Edit the web part on the page and you’ll notice the “Edit Snippet” in the contents of the Script Editor web part.
Select “Edit Snippet” and we are presented with a dialog box to enter our embed code. I chose a random video from YouTube. J
Click “Insert” then “Ok” on the web part properties. Save and Close your edits using the link in the top right. I like how the web part defaults with no chrome (no Title). All done!