channel 4 values

So I’m trying to make a basic code that controls a 2 motor drive with just the left joystick, so I made this simple code.

#pragma config(Motor,  port1,           Lmotor,        tmotorVex393_HBridge, openLoop)
#pragma config(Motor,  port2,           Rmotor,        tmotorVex393_MC29, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard               !!*//

task main()
	while (true){
		int leftpower = vexRT[Ch3] - vexRT[Ch4];
		int rightpower = vexRT[Ch3] + vexRT[Ch4];
		motor[port1] = leftpower;
		motor[port2] = rightpower;


I don’t have my robot or controller with me, so I can’t test this, but I don’t know which direction I would have to push the joystick in order to get a positive value from channel 4. can someone tell me this?

Also, this is actually my first time with this software, so if these are any mistakes, please let me know.

I think this was already answered by the community.
Channel 4 if the left joystick X axis, positive is to the right.
Channel 3 is the left joystick Y axis, positive is upwards.