Further reading
- Salesforce campaigns: https://help.salesforce.com/articleView?id=campaigns_def.htm&type=5
- Salesforce campaign members: https://help.salesforce.com/articleView?id=campaigns_members_working_with_parent.htm&type=5
- Campaign hierarchies: https://help.salesforce.com/articleView?id=campaigns_hierarchy_setup.htm&type=5