Click the option button to the right of the center button. Scroll down and select "check application for update." PSN only affects who you can play with, not if you can update the game.
PlayStation will send you an email with a code, or if you do it through PlayStation Store on your PlayStation. Your subscription will begin as soon as your payment goes...
The next safest surface would be a room with carpeted flooring. That way if you fall it won't hurt as much. Place pillows around you to soften any falls.
