First you will need a subscription/ membership to Gamefly, then go to Rent on the top left, and select the console you want the games on, you can then search that for any games available.
When you find a game you wish to Rent, click the bottom along with the game that either says Rent, or Add to GameQ.
For more information, contact the support team at email@example.com,
Or me personally at firstname.lastname@example.org
(I am not associated with Gamefly, just an honest customer, who wants to help.
Have a great day!