You mentioned two icons, I have no idea what you just told me.
The icons are the little pictures at the top of the Add Reply box you see at the bottom of this thread. They look like this:
The ninth icon (just to the left of the smiley face emoticon) is the Inset/edit video icon.
You demonstrated the ability to copy and paste a hyperlink, so there are just three more steps.
- Click on the Insert/edit video icon
- Paste the YouTube link in the box labeled "Source"
- Click the "OK" button.
Try it to be sure you can do it. You can delete the reply afterward if you want.
What, me worry?