Instructions For Mac:

To create a Zip Archive using Mac OS X, either Control-click on the file or folder and choose Create Archive. Or you can click on a file, then go to the Action menu (the button that looks like a gear up in the Finder window's toolbar), and choose Create Archive from there. Either way, it quickly creates a new file, with the file extension ".zip". This is the compressed file. A file will be created named "Archive.zip" Please be sure to change the name of your zipped file to something relevant prior to uploading.

Instructions For PC:

To create a Compressed ZIP using Microsoft XP or later, right click on the file or folder and choose Send To in the drop list. In that drop list click on Compressed (zipped) Folder. Please be sure to change the name of your zipped file to something relevant prior to uploading.