Legacy GM Question regarding touchscreens & multi-touch


So I'm currently working on adding touch control arrows to my game. My game would require split touch control (e.g. D-pad on the left, joystick on the right.) I'm wondering what is the best way to go around doing this, so my game could essentially recognize multiple clicks in multiple places at the same time (and maybe even radius of a touch). Thanks for taking the time to read this!