need some guide about buying HB key

hi....may some devs guide me how can i buy a HB key from here Honorbuddy the Bot for World of Warcraft

and then attach my key here http://ift.tt/1CtvMKT?

cuz i cant buy an HB key right from http://ift.tt/1CtvMKT....

then i dont know how to buy an HB key to download profiles that i need from http://ift.tt/1IZ4coW

need some guide about buying HB key