Select the Manage My Organisation workflow which allows you to create a organisational tree.

A Division is normally the top level item but this maybe different in your case, as we allow our clients to rename the organisational elements. Please select the top level item for your organisational structure. You may now create an organisational chart of your structure.

As you create the structure you will note that you can set approvers on each organisational unit. If set then that user will be able to see the plans and documents for that area and be able to approve these plans.