The procedures are described in your water heater's manual.
But, briefly:
- DO NOT remove the styrofoam
- Both the anode and the electric element are accessed from the outside of your r-pod via the water heater's access panel
- Before you begin, make sure that you are not connected to share power and that your battery is disconnected.
- The anode is also the water heater drain nut - its a very large hex nut at the bottom of the water heater. Unscrew the nut; attached on the inside of the nut you'll see the anode rod.
- The electric element is also removed via a hex nut. Beside the drain nut, there's a small tin box on the water heater. Unscrew the lid of the box and inside you'll see the electrical connection. Disconnect the electrical and unscrew the element plug.