go to Windows>users>polycade>appdata>roaming>polycade>emulators>mame
and double click mame.exe.
Mame menu will open. you can leave the left pane as Unfiltered. Scroll down in the middle pane and highlight the game you want to configure the joy stick for. the game should be in bold white letters. i think that means its an avialable game. not all my games showed up in bold white letters so not exactly sure.
anyway, hightlight the game with your mouse with the blue bar, and click Configure Options>General Inputs>Player 1 Controls.
Scroll down to AD Stick X Analog Inc and click it. i hit delete a few times until it said NONE to clear all key assignments. then hit Enter and move your stick to the Right. the assignment should now say Joy 1 DPAD RIGHT. Next go to AD Stick X Analog Dec, delete to clear assignment, Enter and move stick to the left. assignment should now say Joy 1 DPAD Left. Next go to AD Stick Y Analog Inc, clear to None, Enter, move stick down. Joy 1 DPAD Down. go to AD Stick Y Analog Dec, clear to None, Enter move stick up - Joy 1 DPAD Up.
when done hit ESC, ESC and Save Configuration. you will get a pop up message that says configuration Saved. ESC, ESC to get out. Relaunch Polycade, launch the game and flight stick should work.
any issues give me holler.