Problem joypad (8Bitdo) con Dragon's Lair on 3Do

I seacrh to play Dragon’s Lair (3Do) on my FireTv…all is ok graphics, video etc…but i have a problem with my gamepad that is 8Bitdo Controller Bluetooth Pro 2 that work well woth all others emu as Neogeo, Ps1, Psp etc… I try so set my controller

but I can’t set them in any way. Reading istructions of roms the keys are: Joypad Up (U) Move Dirk forwards.
Joypad Down (D) Move Dirk backwards. Joypad Left (L) Move Dirk left. Joypad Right ® Move Dirk right. B Button (S) Swing Dirk’s sword. Pause Pauses the game. …and I can’t set the B Button (S) Swing Dirk’s sword.

So pls there is a preconfigured set on retroarch for this games and if not in which way a can set manually the controls ?

Thank Hispa

In quick menu > controls (which is where you should be to move core functions around), you need to cycle through the available commands using left/right rather than pressing a button to map it.