Sit and relieve your bowels. Dispose of your toilet paper. Dual flush toilets are usually of a more modern variety. Look for signs that show you which button is which.  Some dual flush toilets have decals that tell you how much water each button offers. Others will have larger buttons for the larger flush and smaller buttons for the smaller flush.  In some cases, dual flush toilets will have up-and-down levers instead of buttons. If this is the case, look for signs that tell you whether to pull the lever up or push it down (based on whether you have deposited liquids or solids). You’ll need the smaller flush for liquids and the larger flush for solids. Be sure to push the button firmly, as far as it will go, but don’t hold it down for more than a second.  Dual flush toilets usually offer a .8 gallon flush and a 1.6 gallon flush.

Summary:
Sit down and accomplish your task. Locate the buttons on the top of the toilet. Push the appropriate button.