You can create Outstream video directly in the Centro UI.
1) Select “New Ad”, you can use “Video Ad” for hosted file or "VAST" ad if you have a VAST/VPAID Tag.
Enter a name for the ad, upload your video. File must be an MP4 smaller than 100MB, and 2048x1080 max resolution
If you have a VAST or VPAID Tag.
Targeting Sharethrough Outstream Supply.
Once your ad is created you can create a video campaign.
1. Go to the "Advanced Campaign" section and select Video
a) Make sure to select the following criteria:
Placement Type : Out-stream and Unknown
Player size : In order to maximize scale uncheck all
Skippable Ads : Doesn't apply to sharethrough, leave it all selected.
Playbak method : All our videos are auto-play with sound off
2. In the inventory tab look for Sharethrough as an Exchange and you are good to go (you can also use one of Sharethrough deal already in the deal library, here is how)