MegaMegaMonitor comes in two flavours. Most users like the new (beta) version, known as v15x: it's got support for more subreddits and extra features. Click the button to install MegaMegaMonitor. GreaseMonkey/TamperMonkey will detect it as a "UserScript" and offer to install it for you. Afterwards, it should automatically update, but you can always come back and install it again if it doesn't.
If you'd prefer to use the v12x (legacy) version, which has better performance for some users, you still can (for now).
As you explore Reddit, look for the icons that identify the highest MegaLounge that everybody is at. Red 'plus' icons identify people who are higher-up than you are. White-on-black icons identify people on the level you're currently looking at (perhaps they need gilding to help them up the chain!).
Discuss, share screenshots, etc. in /r/MegaMegaMonitor.