Each button is an ordinary component that says which action it presses: useTouchAction('left') in its body holds 'left' while a finger is on it. One Button component made four times with four props is the whole pad, with no names to keep in step. The game reads actions.isDown('left') whatever pressed it; a thumb sliding from ◀ to ▶ moves from one action to the other, and two thumbs work at once.
Hold Ⓑ to charge a shot: actions.heldFor('fire') says for how long, still set on the frame it is let go. The buttons light with usePointer().isPressing(button). On a computer the keys work too (← → Z X), and the mouse presses the buttons.