Instructions
Attempt to cross the "Haunted Wasteland" as Old Link, not Young Link. Part of the plot of the game involves time travel, and you will play through various dungeons as an older and younger version of the same character. You can only cross the Haunted Wasteland on foot if you play through as Old Link. Remove the Master Sword from its perch in the castle to switch from the young version of the character to the old version, if applicable.
Equip the Hover Boots onto your Old Link character through the equipment menu screen. One of the areas of the Haunted Wasteland that you must cross is the River of Sand. If you choose to proceed on foot as opposed to using your long-shot device, you have to have the Hover Boots equipped to accomplish this.
Proceed across the River of Sand using the Hover Boots. Once you get across to the other side, move to the flag in the distance. Stop at the flag and look around for the next flag. Walk to the second flag. Continue this process until you reach the opposite side of the Haunted Wasteland. Use the flags as a type of rudimentary road map to guide you from one end to the other.