See Bernheim's website for upcoming events, hours, and closures. bernheim.org
You can park at the Visitors Center and catch a dirt path descending to the trail on the right of the Visitor Center, by the swings, or you can work your way around the Visitors Center and catch the paved trail as it breaks from the road. Follow the paved path around in either direction. The path is paved or gravel the whole way. You can chose your own adventure, as you can make a figure 8 pattern following this path. Watch for where the Prairie Trail comes off on the prairie side of the pond and takes these seasonal path as you interest, or continue along the loop. Take lots of breaks if you wish, as benches and trees abound on the path. Don't worry if you don't know what kind of tree you are sitting under, most are clearly labeled. Watch out for the geese though, they enjoy a lot of freedom and can cause a mess.