I just checked with YouTube ads for promoted video.
You need to have AdWords account, so creating video ad is like creating normal advertising campaign with the keyword bidding.
1. Sign in to your Google AdWords account, or, if you don't already have one, sign up for Google AdWords.
2. Create a new ad, choosing "Display Ad Builder". Within Display Ad Builder, go to "Video" and choose the "YouTube Promoted Videos" template. Compose your ad.
3. Using the AdWords media picker, choose a video from YouTube.
4. Review and save your ad. Then, complete your other campaign settings and you are done.