I've been using this program for a long time now, but I haven't figured out how to create a shared folder for other Dropbox users... Can you help me with this?

In the context menu of Explorer you will see the "Dropbox" item, where you will see what you can do additionally with folders and files. And for sharing, you will need to install Dropbox on another computer, specify your valid account, and get all the actual copies of the cloud. There's also dropbox app for mac if you're not comfortable using it that way.

Now all the information that is in your Dropbox folder can be synced between the Dropbox cloud server and any of your computers or non-your computers.