The Vircon32: C API reference page may be helpful - http://www.vircon32.com/api.html

• There should be a sprite for at least a background, the snake's body and the food if you want to make your snake just a normal looking square.
• Some good free sprite software's would be GIMP , Microsoft Paint, or maybe even Photoshop on a school computer.
• A link to GIMP download: https://www.gimp.org/downloads/
• You could also have a death screen for when your snake dies.

There is obviously your arrow key inputs but there are other buttons available as well. At least for gamepad(0) we have button_?_ = ? for the average keyboard:

• A = X
• B = Z
• X = S
• Y = A
• L = W
• R = W
• Start = Enter Key

When making you gamepad you'll make gamepad_direction values, WalkX and WalkY for example purposes.

• If WalkX < 0 then that mean you're going left.
• If WalkX > 0 then that mean you're going right.
• If WalkY < 0 then that mean you're going up.
• If WalkY > 0 then that mean you're going down.

With those you would probably make it so that when WalkX < 0 var = 1. And then do:

if( var == 1 ) {
  Snake.X -= PlayerSpeed;
}

to make your snake constantly move after pressing an arrow key.