Tasks and notes can be added in two places - the Lead Summary Page, and once an install is created, the Install Tracker.
Notes
Notes that do not require any notifications or actions taken can be added in the Notes section. In the Install Tracker, they can also be assigned to a specific milestone. Notes in the install tracker can be visible to customers if the "Customer Facing?" box is checked or internal only if it is not.
Tasks
Tasks can be assigned to a user. The assigned users will get an email or SMS notification that they have been assigned to a task, if notifications settings are on. Users can also set up a due date and due time and notify other users when a task has been completed.