The participant details page has multiple sections based on the setup of the event.
Day Licence Code - this is a section to input your membership number - if you are not a member then a Day License charge will be added to your registration and must be paid in order to complete your registration.
Membership Discount - this section allows members to enter their membership number to be eligible for a discount.
Included Item - this is the item that is included as part of your registration at no cost.
Additional Questions - this is a questions section for details about yourself for the event.
Donations - you can add a donation to the Event's nominated charity (or multiple charities)
Registration Add Ons - these are extra items you can choose to add to your purchase.