How to open .pde file? I am getting error with import

Hi,
I have seen only .ino file for arduino. Now I can see there is .pde file and when I try to copy and past it into arduino I am getting error.

Here is a GetHub page with .pde file
https://github.com/WorldFamousElectronics/PulseSensor_Amped_Processing_Visualizer/tree/master/PulseSensorAmpd_Processing_150

The first file: PulseSensorAmpd_Processing_150.pde gives me
exit status 1
'import' does not name a type

Please help.

[table][tr][td]/*[/td][/tr]
[tr][td][/td]
[td]THIS PROGRAM WORKS WITH PulseSensorAmped_Arduino ARDUINO CODE[/td][/tr]
[tr][td][/td]
[td]THE PULSE DATA WINDOW IS SCALEABLE WITH SCROLLBAR AT BOTTOM OF SCREEN[/td][/tr]
[tr][td][/td]
[td]PRESS 'S' OR 's' KEY TO SAVE A PICTURE OF THE SCREEN IN SKETCH FOLDER (.jpg)[/td][/tr]
[tr][td][/td]
[td]PRESS 'R' OR 'r' KEY TO RESET THE DATA TRACES[/td][/tr]
[tr][td][/td]
[td]MADE BY JOEL MURPHY AUGUST, 2012[/td][/tr]
[tr][td][/td]
[td]UPDATED BY JOEL MURPHY SUMMER 2016 WITH SERIAL PORT LOCATOR TOOL[/td][/tr]
[tr][td][/td]
[td]UPDATED BY JOEL MURPHY WINTER 2017 WITH IMPROVED SERIAL PORT SELECTOR TOOL[/td][/tr]
[tr][td][/td]
[td][/td][/tr]
[tr][td][/td]
[td]THIS CODE PROVIDED AS IS, WITH NO CLAIMS OF FUNCTIONALITY OR EVEN IF IT WILL WORK[/td][/tr]
[tr][td][/td]
[td]WYSIWYG[/td][/tr]
[tr][td][/td]
[td]*/[/td][/tr]
[tr][td][/td]
[td][/td][/tr]
[tr][td][/td]
[td]import processing.serial.*; // serial library lets us talk to Arduino[/td][/tr][/table]

I think that code might be intended to run under Processing on a PC.
PulseSensorAmped_Arduino would seem to be the Arduino code.

(sorry about the table codes, tr & td)

If you read the instructions:

You'll see that https://github.com/WorldFamousElectronics/PulseSensor_Amped_Processing_Visualizer/tree/master/PulseSensorAmpd_Processing_150 is actually a Processing sketch, thus the import error. The Processing sketch runs on your computer. The Arduino sketch you need to upload to your Arduino is the PulseSensor_BPM example sketch included with the PulseSensorPlayground library.

The reason you will sometimes find old Arduino sketches with the .pde extension is because the Arduino IDE was based on the Processing IDE and for some reason it took Arduino a long time to get around to changing the extension.