Once you reach one of the entrances to the park and buy your tickets it is time to continue on foot. Walking paths are excellently organized and will lead you through all sixteen lakes, crossing over travertine barriers and allowing the best views of the waterfalls and other interesting spots.
Walking routes are colour-coded and once you decide which route you'll take you just have to follow the signs along the route. Most routes overlapp somewhere in the middle of lakes, making paths busy and occasional pedestrian traffic jams may occur.
Since there's a lot of walking ahead of you make sure you bring appropriate shoes. In some parts (especially near waterfalls) paths become wet and slippery. In the winter snow is cleaned but ice can make them dangerously slippery.