Re: how to place ads on youtube home page?
I am not sure that what you are seeing is a Video Ad, but to get a Video to appear as an Ad on the youtube home page can be done by contacting your AdWords account manager. It cannot be done directly from your AdWords account by you.
More details here :
"The desktop video Masthead is a 780x195 video ad unit that can only run on the YouTube homepage. It includes a video and auto-generated information panel."
Creative Submission and Turn-around Time
- Assets must be received by YouTube no later than 4 (four) business days prior to campaign start date. Send them to your Account Manager and Media Solutions Consultant"