Here’s how to put a .prc file on your Kindle:
Save the .prc file to your computer. Then attach the usb cable from the Kindle to your laptop, then wait for the directory window to come up. The page on your Kindle will change, but you don’t have to pay attention to that.
Open the “open folder to view files” folder, then open the documents folder.
Then copy and paste the .prc file from your computer into the Kindle’s directory. Then you can close all the folders and detach your Kindle from the computer. On the Kindle, the regular menu will reappear.
Voilà! the file will be in your Kindle’s menu.