There is no option to assign controls - luckily my ‘retro’ joystick is the Sidewinder Precision Pro, which is this game’s preferred stick (promotion or something) so I’m lucky there. My stick has an old 15 pin joystick plug, but came with an adapter for USB. I was amazed how well it works with the Ka-50 in DCS World.
I actually bought that stick for playing MechWarrior 2 3Dfx - something it was very good for.
Swing that lamp and pull up a sandbag! 