There are two philosophies on how to structure your campaigns with regard to how Meta distributes your ad spend across campaigns, ad sets, and ads: campaign budget optimization (CBO) and ad set budget optimization (ABO).

CBO is a platform feature where Meta's AI takes control of how your campaign’s budget is allocated to its ad sets. You can turn this option on during the campaign creation process.

But with an ABO strategy, you manually decide how much to allocate to each ad set—not Facebook. You set this budget at the ad set level.

When and how should each strategy be used?

Meta's AI is increasingly getting far better at picking than a skilled media buyer. Given you're also new to media buying, it's logical to conclude that Meta's AI will likely significantly outperform you ;)

We recommend using CBO as your default. Only use ABO if you, for some reason, want granular control and think you can outperform the AI.