Pelican Parts Forums - Difficult to shift into reverse gear

Hello 996 Gurus:
Recently, I have been experiencing resistance when I want to shift to reverse gear (2001 Carrera 4). I have read, probably all related threads, but have not got much! One of the threads stated that one could adjust the reverse cable (within the gear snifter console); but, how it is done was not explained.

Any hint would be appreciated. BTW, I know one can do various tricks to get the car shift into reverse, including going to the 2nd gear first, etc; however, I need more constructive instruction.

BTW, I changed the gearbox fluid last year. My fluid ran out before the level of fluid reached to the bottom of the hole from which you can test the fluid level. The level was short by about 1/4". That should not cause this issue, should it? In any case, I am topping the fluid up this week-end; just curious about it.
Thank for your attention to this issue in advance.