On/Off button or Kill Switch
Hi Les, what you have on that switch are JST connectors. Sometimes known as BEC connectors. The RX end will fit your receiver . You can plug it in any free servo socket. Just make sure red is on the middle pin and black towards the outside of the RX case.
Then you only need to match the plug on the other side of the switch to your battery, which unfortunately you omitted to show us 🤔
Looks like the receiver has the standard JR type plugs.
Cheers Doug 😎
Young at heart 😉 Slightly older in other places.😊 Cheers Doug