To set up Departments, Managers, Employee in odoo you will need to go to the menu Odoo Employees. Here there are all related menu items that will guide you to create employees, department, manager and Division(Parent department).
1. With reference to the screenshot below you can start with creating departments first.
2. If there are child departments associated you can create them and tag previously created parents over there.

1. Tag managers and complete the process.
2. Based on the second screenshot you can navigate to employee menu and update details. 

Navigate to the settings menu like-Employees>> Department >>
Navigate to the settings menu like-Employees>> Employees >>