Don't you have to post them to a video hosting site first? then post the link to that site? This how one forum of which I am a member works, and that includes photos. But maybe this site has different protocols.
As the above poster said, you can post them on YouTube pretty simply for free. Your other option is to go to your profile on here, under "My Scenes" click Add Downloads or Video, browse the video and upload to your bin, then add it to your profile's videos. Good luck!