To add a new attendee click the "Add" button next to "Attendee Information" shown in the image below.
This will take you to the "Registration Process" where you can select any appropriate price tiers for the attendee. You are not required to select a price tier. If there is a cost associated with the price tier(s) you will be required to enter a valid credit/debit card further down the page.
The next section is where you can enter the Attendee's personal information.
If payment is required to complete the registration that information will be entered below.
When you have finished click "Pay Now"/"Finish Registration" to save the Attendee, the Attendee will not be checked-in at this point.