Some Newbie Questions about f-15

[ComManDerN7]

Sorry for the vague title but i am having some control issues with the f-15

 

-first for some reason when flying it always wants to roll left, no other plane does this so i know its not my stick (an extremely outdated xg900) trim does not seem to do anything for any aircraft.

-ATT hold only works sometimes and ALT hold never seems to work

-What does CAS option do, hitting Ctrl+1 just puts my plane into a dive

[Overvolt]

For the first question, I had a problem like this, spent a lot of time trying to find out what was happening, I discovered it was another plun joystick on PC. Today when I'll fly just let my hotas connected.