Before you start, the only tool that you will need for this is a size 3 allen wrench.
Locate the display screws circled below and then proceed to remove them with your size 3 allen wrench. Once these are removed you can pull off the display as seen below.
After this, locate the control buttons on the left handle. There will be one screw that will need to be removed.
Next, unplug the display connection to the wiring harness. The Radrover, Radmini and RadCity will all have silver connections that will need to be unscrewed before being disconnected. The Radwagon will simply pull apart and will be a green connector.
Now you can safely remove the display and replace with the new one.