Oh its easy:
Home: all the peeps you follow specifically, and their boosts
Notifications: all the interaction with your toots
Local Timeline: the public toots of your specific instance
Federated timeline: all the toots of all the instances connected to yours.
TOOTS
add picture (+description)
Privacy level : public, public but unlisted, followers-only, mentioned users only
Content Warning: for labeling content and hiding the body.