Need practical 2 Hours session of Bitbucket Repository branches

We need an expert in Bitbucket Source Control to help our development team leader to understand in practical how to manage the application Repository with many branches.

1-We have an application project consists many Modules. Each module has its Class Libraries in business Layer & Data access Layer .

2-We need to control teamwork to allow each developer access and develop only a subset of the app (Class Library), and never getting access to the whole the source code; while the team leader access and merge all modules in one application.