All the files are in a compressed archive (.zip), you will need to extract them using something like
Winzip. Each file contains the .bas source code to open in qbasic, and a compiled, stand-alone executable of the programme.
This is a small application to makes the computer work a bit like a signal generator, allowing it to play almost any frequency sound, from 37Hz to ultrasonic. If using a computer where PC speaker control if routed through the soundcard, make sure to turn the PC speaker on.