It's a bit difficult to see from the picture, but it looks like 你 are buying SimPoints from the website?
If that is a mistake and 你 do not want to buy any SimPoints, 你 can close the web page and your account will not be affected.
However, if 你 DO intend to buy SimPoints, I think you're at the page where 你 need to put in your payment details. 你 will need to choose how 你 are going to pay for them (have a look at your debit card/credit card and find the option that matches) and put your details in while following the instructions on screen.
Just so 你 are aware, SimPoints do cost REAL money. They're a type of online currency on thesims3.com that 你 use to buy things from their online store. So don't put in any of your details if 你 did not mean to spend real money!
