Combining two arduino sketches

Hi, I have 2 separate sketches which work fine on their own. I am struggling to get them working on one arduino.

Sketch number 1:
Deals with the input from a microwave doppler sensor

Sketch number 2:
Is a piezeo buzzer

I would like the microwave sensor to activate the buzzer once a threshold it met (I have already got an LED lighting up when the threshold is met) but I cannot combine them.

Below is the code for the microwave sensor: Can anybody tell me where to put...

Combining two arduino sketches