Measure the depth of the boots from the top of the shoe to the bottom of the inside. Add 3 inches to this measurement and cut a 1-inch dowel at this measurement for each pair of shoes. Add 7 inches to the boot depth measurement and cut a 1-inch dowel at this length for each pair of boots. The first set of dowels will hold your front row of boots, and your second set will hold the back row of boots.
Drill a pair of 1-inch-deep, 1-inch-diameter holes in the board for each pair of boots. Space the holes within each pair 8 inches apart so they're each 2 inches away from the edge and space the pairs 4 inches apart.
Insert a dowel into each hole and screw through the bottom of the board, into the dowels.
Set the insides of your boots over the front row of dowels so they're perpendicular to the board and pointing away from taller row of dowels. Set the rest of your boots on the second set of dowels so they hang over the first set.