Login with your Facebook account so you can use the site.
You receive money by asking someone to pay you. You enter the amount you want to receive and the other person scans the generated code with his smartphone.
You currently don't have any money on your account. This is no problem if you only want to receive money in which case you can ask someone to pay you. If you want to be able to pay others you can fund your account with a wire transfer of by credit card.
This wizard will initialize your smartphone with your account and ask you to protect your account with a pincode. After that you can scan a code from someone else and pay him.