I tried it but it still did not work.
What precisely are you trying to do? Are you trying to have a video/stream permanently on your front page, like a welcome video (at which point the embed option Kyle mentioned is the best option) or are you trying to add a video into a forum/news post?
To add a video into a forum/news post (or even into a wiki page), do the following:
Go to the video you want to put into your website, and copy the URL from the address bar of that video:
Click on the "insert video" button:
Paste the URL you copied earlier into the "source" section:
That will show a "placeholder" for the video:
You can then press the "Preview" button to ensure it has pulled the correct video across:
I'm not sure what to suggest if this process isn't working for you, other than perhaps you try it in a different browser.