As well as the breaks that apply automatically, you can add your own breaks and record callbacks on your timesheet.
Adding a break: against the relevant day, click Add Adhoc Break. Enter the break's details and an optional note, then click Save.
Adding a callback: click Add Callback, fill in the callback details and click Save. Callbacks can only be added where an administrator has set up a matching callback template, so if you can't add one, contact your admin.
Both breaks and callbacks you add are marked Pending until an administrator approves them.