Sorry for the delay in replying...
Basically here are the steps.
1. set up your Section(s) and ProposalSection(s)
2. run the create_review_permissions management command. This will create a django permission "can_review_{section_slug}" for each section.
3. create a Team (or Teams if different sets of people are reviewing different sections)
4. in the admin, on the detail page for the team, add the "can_review_{section_slug}" under "permissions" for whatever sections you want that team to be able to review
5. use the normal site UI to manage team membership
Let me know if any of these steps need further elaboration.