BuddyPress.org

Check out the BP Skeleton Component:
https://wordpress.org/extend/plugins/buddypress-skeleton-component/

It teaches you how to create a whole plugin for BuddyPress; you won’t need to use all the code in the skeleton component, but it’ll help you structure your code for BP.

The functions you want to look at in particular are:
`bp_example_setup_globals()
bp_example_setup_nav()`

Both are located in bp-example-core.php.

Hope that helps.