How do you wire properly a cpap to use the pwm signal for cooling

[Alphablock33]

Hey everyone , 

So i have a stealthburner that is not the best for my required cooling and i stumble upon a video from Vez3d in which he show the power of a cpap fan for his cooling need , i did order one and follow his wirering diagram .But after i connect everything the fan start blowing all the time which isn't what i want for when i print ABS or stuff that don't really need that much cooling .i did found on, the forum someone who proposed the Opto Mosfet to create a pwm signal to control the fan .Does anyone use them ?If so how do you wire them without breaking anything .Or do you have other way to control this fan .

Thanks