I hope this helps.
BIND THE RECEIVER TO THE TRANSMITTER (copied from manual)
1. Turn on the Tx.
2. Apply power to the Rx.
3. If the Rx LED flashes once and then stays on, the Rx is already bound to the
Tx and you can skip to the next section. Otherwise, insert a small diameter
screwdriver through the hole marked “BIND” and press the pushbutton until
the Rx LED glows red and then turns off after about one second.
4. Release the “BIND” button.
5. If the binding is successful, the Rx LED will flash once and then remain ON.
6. Test for proper Tx/Rx functionality in the next section. If the radio doesn’t
appear to have become properly binded, repeat steps 1–6 above.