The red wires go to the ESC
The blue wires go to the motor
The green and brown are the crossover jumpers
A microswitch is a fast acting switch that can be easily operated by a servo with a wheel style output arm cut into a cam.
They come in MANY sizes...
You want the microswitch to be rated at a minimum for the same current as your ESC. Generally that will mean having it be rated for a lot more voltage than you need.