Pulse Sensor Amped Not Working

I am new to arduino and programming.
I have just bought a pulse sensor. Unfornately when i run the example code from the website:

The led on the sensor itself or one wired into the arduino doesn't flash no matter how I touch the sensor.
Any help?
Thanks

AllSerialHandling.ino (2.48 KB)

Interrupt.ino (5.61 KB)

PulseSensorAmped_Arduino_1dot4.ino (3.08 KB)

Timer_Interrupt_Notes.ino (7.5 KB)