The set up process is pretty simple. You'll need to authorize Dropbox Automator to access your files to get started, and when doing so it'll show up as Wappwolf—the service that powers it. Once you've got that out of the way, you can select a folder you want to use for automation. Unfortunately you cannot create a new folder from within Dropbox Automator, so if you want to add a new one you should do that on your local machine before you log in (or just reload the page if you already have). Once you select the folder you want, you can start assigning actions from the provided list. They're all pretty self-explanatory, but the labels on some of the action options are not as human-readable as they could be. If you read them carefully they'll make sense, but currently they appear to be labeled by their method names. Once you're past that little bit of confusion and you've selected all you're actions, just save your choices and you're all set. Now any relevant files placed in the Dropbox folder you chose will be subject to the automation you set up.
Note: Processing takes a minute and the results will show up in a folder called "results." A folder called "processed" will appear first, containing the files that were just processed. Those will be the unaltered copies. Wait for the "results" folder to appear to see the actual results.
This is a very useful tool that can do a lot with the stuff you keep in your Dropbox without any work on your part. It's still a little rough around the edges, but definitely worth a look.