ok i want to build a VERY simple robot for some science thing at school
i want to have it 2 track tank like design so it will have the in place turning
so i'm thinking i'll build a chassie put some treads on and 2 dc motors. and it will be wired up somehow so the four functions (forward, right, left, rev) will be controlled by 2 DPDT switches
this will be in a wired controller

and since i'm just feeding power directly to the motor's they'll move really fast and i need someway to slow them down yet still have plenty of torque as the robot will be moving pool balls (yes pool balls)

i found this to use to move the robot, but i dont know how it goes in reverse, do you have to reverse the voltage to do that?

i also need some mechanism to manipulate 1 or 2 pool balls, maybe a fork life thing, pistons, or i dunno something
this would need to move between 2 predefined points, how would i do that?

THANKS FOR ALL YOUR HELP!

im sorry but i dont know ANYTHING about this robotics thing
so with the H-bridge how woulld i control the motors?
i know what PWM is but how would i go about controlling this and how to make it work along withe the H-bridge

i also have NO IDEA on which parts to get
i would REALLY appreciate it if you could recommend some parts which will do the job
thanks again