RGB Shield for Arduino R3 to control 12v RGB LED strip

Hi there everyone!
I've bought an RGB shield for Arduino used to control 12v RGB LED (non addressable) strip.

I'm only just starting out and having trouble trying to figure out the physical hardware circuit/setup. I'm scared of blowing something up.

So I've got: 12v RGB LED strip, the shield, an Arduino R3, MOSFETs Stripboard (we're linking up the maximum 2 x 5m strips) and i'm going to buy a proximity sensor.

I want to set up the strip so that it flashes white when the proximity sensor detects a person.

Can someone help explain what I attach to what? I know I sit the Shield to the Arduino, and the 4 wires of the strip go into the grey holes that dictate 12v, R, G and B. I've been told i'll need a MOSFET but i'm not 100% sure why or where in the circuit it sits. Then I'm not too sure where to put the proximity sensor either.

Is anyone able to help link to appropriate tutorials? Or help explain on here? I'm having trouble finding good tutorials online that explain what i need to do...

Any help or advice would be appreciated!
Thanking you kindly in advance,
Sophie