You will need the following information available, so please have this to hand:

Your Booking Reference.

Passport or other eligible travel document for the lead passenger.

Passport information including document number, expiry date, date of birth and place of birth for any passengers you are travelling with.

You don't need to provide the information for all the passengers in one go. You can save the information for those passengers you have available and then return to complete the others at a later date.