First off, you will need to manually find one server IP to get started. Just go to a random server list website and copy one of the IPs.
Then paste that IP into Server Finder, optionally configure the maximum amount of threads and press the “Search” button. More threads make it run faster, but also require a faster computer and a faster internet connection. If you’re not sure, just leave it at the default value of 128 threads.
Once Server Finder is done, and you go back to the server list, you will notice that some of the servers it found will be broken. Wait until all servers are done loading, so that you can see which ones are working and which ones aren’t.
Then click the “Clean Up” button and run a Clean Up with the default settings to get rid of the broken servers. Make sure that your Clean Up settings match the ones in this screenshot:
And that’s it. I found 285 servers this time. How many can you find?