Playing as England, you just need to build a Settler unit and found a city far away from any of your other cities, preferably near another civilization, or even better, between two cities that belong to another civilization. Founding said city on a different continent to your other cities also helps. When looking for an ideal place to settle, look for the numbers on the map which represent the projected loyaly. The lower this number is, the more likely the city you found will become disloyal.
Once you found your city, install Reyna (the financier governor) into your new city, then wait for the rebellion to come. If you've founded your city near another civilization, the loyalty pressure from their cities should make your city rebel. If you hover over the loyalty icon on your city name, it will highlight the amount of turns it will take for the city to rebel. Now it's simply a case of waiting until your city becomes a free city and then the achievement will unlock.