http://sn-zw.facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd.onion/business/help/835561738423867
When you select Flexible as your ad format, you can select up to 10 images and videos in a single ad campaign, and the ad delivery system will automatically determine what media or media combination, such as single image, video or carousel, to show to people. You can only select Flexible as a format in the ad setup section at the ad level in Meta Ads Manager if you create the campaign with the traffic, engagement, sales and app promotion ad objectives.