Non-billable time can be entered through the Timesheet Manager, the Time Clock and the User Daily Budgets screen.
Timesheet Manager
Time Clock
User Daily Budgets screen
Adding Non-billable time
Adding Leave
The add leave window is very similar to adding a non-billable item. The window will have further options allowing you to enter a full week of leave for one user, or enter a public holiday for all users. Not all users will have access to this menu. It is often used by Practice Managers.