In currency exchange, there is always one currency that is bought and one that is sold (the sold currency is usually used to purchase the bought currency). The currencies bought and sold are determined by two things in the order form. Firstly, whether the "buy" or "sell" button on the order form is selected, and secondly, which currency pair is selected. If you want to buy or sell the second currency in a pair (the quote currency), you have to think backwards, since the "buy" button will actually sell the quote currency in exchange for the base currency and the "sell" button will buy the quote currency using the base currency.
If the "buy" button is selected and currency pair x/y is selected, then currency x will be bought and currency y sold.
If the "sell" button is selected and currency pair x/y is selected, then currency x will be sold and currency y will be bought.
Click HERE for a more detailed explanation on buying and selling currencies.