A block is a reason for an event that happens in your Activity and Schedule. This could be for annual leave, sickness, a regular event such as fire drills, generic meetings, training sessions etc.
To add a new Block, in the MORE menu > BLOCKS. Click on '+ Add Block'.
Give your Block a name and make sure the required fields are filled. If the Block requires a workflow/approval, select an option in the 'Workflow' drop down.
The block will now appear in places such as ACTIVITY & SCHEDULE on your Add Event drop down list.