Download HeareApp from the appstore, make a route on the HeareApp.com website, input the code in your HeareApp and start walking.
Depending on the quality of your GPS reception, the app knows where you are and uses 3D directional sound to indicate what direction you are facing. The HeareApp uses the standard GPS and compass function of your iPhone or iPad so no extra equipment is needed. The level of detail for your walk is depending on the GPS signal.
The route itself can be made on the HeareApp.com website. You can plan the route from begin to end. By saving the route it will be transformed into a code. This code can be entered in the application, so internet access is not necessary during the walk. By using social media you can share the route code with the world (or just your friends).
The HeareApp virtual guide dog (or other sounds you can choose) will then guide you from point to point until you reach the endpoint of your route. That could be your friend’s house, a train station, the local bar or a barbecue in the park nearby for your surprise party. Note that the sound is not a replacement for being careful and attentive to possible dangers (like traffic, wild animals etc). Don't trust on GPS alone. If you are blind, also use your normal assistive devices like cane and guide dog.
By following the sound you come to the next point on your route. When you have reached the next point, tap on your iPhone screen and you will hear the sound you choose on the next waypoint. This way sound guides you from waypoint to waypoint.