I am sending you four pictures. There is really no way to incorrectly insert the plug if you pay attention to the ridge and grove on the plug and jack, and if you also line up the arrows which are on the body of the plug and the body of the device.
The plug has an alignment grove which is lined up with the axis of the cable
The plug has an alignment arrow which is 90 degrees to the cable and grove
The device has an alignment ridge which fits with the groove on the plug. This grove is at 3 o'clock (the right side of the jack)
The device has an alignment arrow which is at 6 o'clock (the bottom of the jack)
when inserted, the cable is at right angles to the axis of the device, at 3 o'clock.
Please see the four images which I have sent by email.
The device has