It is simple. First, register by clicking here. After that you must put your visa information, and they will take some cents from you just to check your visa. Now, in your Visa statment you will find a something like that: PAYPAL-3939. They need these numbers to activate your account, it will show in your Visa after 2-3 business days, but I will take a day if you have Online Statment(like WataniOnLine).

Now, they will ask to confirm your address. They will ask you to provide bills or anything to confim your address, but you will never find something they ask for to help, because everything in Arabic. After 6 months of looking to something to help me to activate my account, I thought my PASSPORT will help. After I sent a copy of my passport, THEY ACTIVATED IMMDIATELY