If you have created your top-level region, practice or group and want to create sub-regions, sub-practices or sub-groups, do so using the New Region, New Practice or New Group button on the Immediate Sub-Regions, Immediate Sub-Practices, Immediate Sub-Groups related list of the record that you want to be the parent.
Once you have created your regions, practices, and groups, you can check their hierarchy using the Region, Practice, or Group Hierarchy popup.
See "Viewing RPG Hierarchy". You can edit the Parent Region, Parent Practice, or Parent Group field in your records if required.