1. Make sure you have HTML Asset File and Tracker Asset as they are required.
2. Create Creative by using Create Creative API.

Creative Sizes

For each creative size you need to create separate creative by using same asset file.
Properties related to creative size are: width , heightand rewarded_type, they influence the result Ad Format:

• If rewarded_typeisrewardedthen the Ad Format is Rewarded
• Otherwise, if width>heightandheight <= 250px then Ad Format is Banner
• Otherwise, Ad Format is Interstitial

Relevant parameters

Following are the relevant and required parameters to use with Create Creative API:

• name
• tracker_id
• type: must be javascript
• asset_file_id
• width
• height
• rewarded_type
• mraid_type

Additional optional parameters:

• start_time
• end_time
• creative_attributes
• ad_gap_id
• ad_gap_reporting_metric