Advertisers can track conversions through the Native Ads Conversion Report found under the Reports tab in CPA/CPL:
For campaigns that have conversion tracking enabled, conversions can be viewed at this screen.
In order to track conversions, advertisers will need to ensure that the Native Ads Website Analytics Pixel is properly inserted into the header of their website’s HTML. Pixel can be located under the My Websites tab, or in the Campaign Optimization step of campaign settings.
Get more information on the Native Ads Website Analytics Pixel.