What aspects of your campaign are defined at the ad group level?

The ad group level is where you define your target audience and specify how and where you want to reach them through placements. This includes setting audience demographics, interests, and communities, as well as choosing inventory types (e.g., feeds, conversations) and device targeting. Ad creative and messaging are defined at the ad level, which is nested within the ad group. The overall campaign budget and campaign objective are both set at the campaign level, which is the highest organizational level in Reddit Ads.