1) Upload your video file. The file size should be less than 3.5MB, to ensure "Heavy Ads Limitations" will not be triggered and remove the ad from browsers.
2) Remember that the video should have an aspect ratio according to desktop: 16:9
The shown key-message visibility zone is only guaranteed when the viewport of the user follows the 16:9 aspect ratio.
Please note that unlike HTML, video material isn’t fully responsive. For this reason we recommend placing text, logo’s, buttons and anything else of importance in the middle of the creative, rather than close to the boundaries of the safezones.