You would have the matchbox pluged into the elevator on the RX, then one servo pluged into #1 position on the matchbox and used position #1 on the rotary switch, plug other servo into the #2 position on the matchbox and then use position #6 on the rotary switch to set up the servo, as positions #5-8 are the reverse positions on the matchbox. Matchbox instructions are attached. After all adj are done with the matchbox turn the rotary switch clockwise through position 9 to 0 to save the settings before turning off.

Cheers