STEP 1:
Login to your Dashboard and click on the Domains App
Step 2:
Click the Add button and the Add Domain window will pop up.
STEP 3:
Type the domain that you want to purchase, then click Search.
Note: Don't add the WWW on the domain name.
Step 4:
Put a check mark beside the domain that you want to purchase and click Buy Now.
Note: Domains are registered under your name and thus isn't refundable.