Creating a Parent/Child project structure in Hive is simple, and most of the steps can be done on the Project Navigator page!
How do I create a new child project under an existing project?
Create a new project
When creating a new project, choose the parent project in the Location dropdown
This will create a new project under the parent project
How do I move an existing child project under an existing project?
Enter the project and click on the project's settings page
Choose the parent project under Location
Click "Save changes"
This will move the existing project under the parent project
How do I create a new parent project?
Create a new project
Click on the Edit project button in the existing child project
Choose the parent project in the Location dropdown
Click "Save changes"