That page will tell you to [download the required Safari Driver browser extension (SafariDriver.safariextz) here at this link](http://selenium-release.storage.googleapis.com/index.html?path=2.48/).
For that to work, you'll need to [download the Standalone Selenium Server from here](http://docs.seleniumhq.org/download/) and put that JAR file in ``/usr/local/bin/``. To make the next step easier, rename the downloaded JAR file to ``selenium-server-standalone.jar`` (if it's not already called that).
Next, configure the Selenium Server JAR file into your PATH like this:
Now you're ready to run automated tests on Safari if you use ``--browser=safari`` on the command line when running your tests/scripts with SeleniumBase.