After viewing a few videos, I believe my problem has something to do with CH5.
On my transmitter, there is a function called "Monitor". It displays on the transmitter's screen, the various flight controls. However, nothing seems to affect the CH5 slider; none of the sticks or any of the switches.
I do note however that if I hold the spring switch on the upper left (rear) of the transmitter, the transmitter's display shows "BIND" when I power the transmitter on.
On the Modes panel, I changed the ARM from AUX1 to AUX5 and now the Arm indicator is enabled.
However, after unplugging the USB and trying to fly, nothing happens and now the arm indicator is dark.
Also, the lowest Throttle value that I can set using the trim switch is 1006. Max is 1861.
Bottom line: although I've managed to somehow get the ARM indicator to come on, it's not persistent.