Folders
Folders are the primary organizational unit. You can nest folders inside other folders as deeply as you need, and add campaigns and assets at any level.You can also create a campaign at the root level instead of a folder.
Campaigns
Campaigns are a special container for grouping related assets together around a specific marketing effort. You can add folders and assets inside a campaign, but a campaign cannot be created inside another campaign.Assets
Assets are the core items you create in Conversion: workflows, emails, forms, and files. Assets cannot contain other items inside them.Nesting rules
A campaign cannot be a child of another campaign, either directly or inside a folder that is itself inside a campaign.