C. Crane WR-2A - Manual (Page 8)

7
Remote control functions
Many functions of the WR-2 radio can be operated using the
remote control. Some operations require a longer press of the
button.
In this case simply keep your finger held on the remote control
button for 2-3 seconds until the display on the radio shows that the
command has been accepted.
Before the first operation: please remove the small transparent
foil from the battery holder to activate the battery.