Making my own PWM DC motor

[Pete12]

http://www.easterngeek.com/2008/06/simple-and-dirty-pulse-width-modulation.html

I made this (Like the step by step guide told me)

- Problem is the maxium current is only 0.2A.

How can this professional shop's PWM have maxium of 15A ???

http://dx.com/p/dc-6v-90v-15a-pwm-motor-speed-control-switch-governor-green-black-160094

WHAT TO ADD+HOW TO PLACE COMPONENTS TO MINE: IF I WANT TO USE MY PWM about 6V or 12V BATTERIES PACK 18650(2x or 3x)+ max. amperes safe about 3A ???

(Controlling geared 12V high torque DC motor)

LIKE THIS FOR EXAMPLE: http://dx.com/p/high-torque-60rpm-12v-dc-geared-motor-91625

A LIST OF WHAT TO BUY(with ratings W,V,A) and a drawing how to solder things...

Thanks