1. Download the compressed archive from https://www.waterfoxproject.org/downloads You'll get a .bz2 file.
2. Extract it to the location of your choice, keeping the directory structure intact. I chose to extract it to my home.
3. You now have a folder called waterfox. Inside that is a file also called waterfox. Doubleclicking that file will start the browser.
4. It will now offer to import your Firefox data.
5. Set up a menu launcher to that 'waterfox' file so it launches from the menu. Inside one of the folders, in the one called 'browser' and then 'icons', you will find a decent looking icon. It's the one shown below.

Waterfox keeps itself updated; if you open Help => About Waterfox it will tell you which version you're running. As of January 1 2018, the current version is 56.0.1.