From torproject.org:
Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built-in privacy features. Tor provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy.
That’s it. You can start the Tor service by typing “tor” in Run Program (Xfce) or at the command line in terminal. Once it’s running, you can use the Foxy Proxy button to turn on the Tor proxy. Once you’ve done that, you can test by using THIS site.
Nowadays, there's a much easier way to get Tor up and running on your Slackware system. All you have to do is visit the TOR site and download the Linux binary package. Unpack and install it either in /opt or in your /home directory. Create a launcher on your panel for the executable and you're all set.
The TOR binary is a self-contained package; everything the browser needs to run is included. Any mods or preferences you set in your new TOR browser will be saved in its own default profile document. It will NOT affect your regular Firefox ESR settings in any way.
I advise you to read the TOR User Manual in order to gain an understanding of how it works and in what ways it protects your privacy.