You know when you have a document open in two programs at once, like an excel spreadsheet or something, and you make a change to it and that updates something somewhere else? That's a form of piping. Basically just sharing data between programs.

When you're using a terminal, you interact with programs by calling them by name then giving them commands (like a terminal version of googling something would be like "google -imagesearch 'pig poop balls' " or whatever). So piping in this case would be taking the output of that search then plugging it into another program, say Gimp so you can edit the photo output:

"google -imagesearch 'pig poop balls' | gimp -load"

Totally not a real example, but it's how a pipe works. In this case running that command would save you opening google, finding the image, copying the image somewhere, opening gimp, and loading the image in.

if you know how to do things with the program in the command line too, you could do something cool like get an image, load it into gimp, and output a converted version of it or and edge detected version of it or whatever without ever even seeing the image until it outputs to a folder. It can make doing big repetetive tasks super easy. Just define the command, save it as a script, and run it later. Don't even have to look at the gimp code as long as you know how to use the terminal commands.

You type a command. Output normally goes to text on your screen. Put it through a pipe. Now that text can go into a file. Or you can filter it. Or you can send it across the internet. Pretty much anything your computer is capable of doing can now take that command’s output as input. Pipes!

Which part are you having trouble with? I can provide more examples.