No I’m trying to book now. Also I don’t want to pay now, is credit card just to guarantee the booking?
You have to pay online, as per the website instructions.
how do I add extra driver? or shall we do it at the airport on arrival?
You can reserve an extra driver online during the booking process under EXTRAS section. Some suppliers offer it for free, so look out for the "offer" icon next to the vehicle photo.
If not, then on certain models you can reserve the extra driver :-
Agent uploaded: 1616312058532.png
You then pay for the extra driver at the desk on arrival.
IF Extra Driver is not shown under extras. Click on the IMPORTANT INFORMATION link , next to the car photo.