Instructions
Launch "Team Fortress 2."
Click "Shop" from the main menu.
Click the tab that corresponds to the category of item you wish to purchase. For example, click "Hats" to see all hats or "Weapons" to view all weapons.
Click "Add To Cart" in the bottom right corner of the item you wish to buy. Click the shopping cart icon in the bottom left corner when you are ready to purchase your items.
Click "Checkout" to begin the checkout process. If you do not have funds in your Steam Wallet, click "Add Funds" to add additional funds from a credit card or debit card.
Click "Purchase" to buy the items. The amount of the items is deducted from your Steam Wallet.