The Leave page gives you a breakdown of any holiday you have booked.
Your allowances (if entered by your manager) detail how much holiday you have remaining.
If your employer has enabled the Leave Request feature, you can request Leave using the blue Plus button at the top of the page.
When requesting leave, choose the type of leave (only Holiday comes out of your holiday allowance), and start/end dates.
Half-days are set using the AM/PM drop-downs on the start and end dates. Add a message for your employer or manager and hit 'Continue'.
The request will then be sent to your employer or manager. When they respond you'll receive a notification - if your request is approved, the holiday will appear on the rota.