How to implement an AR application?

Question

Unity

What is the best way to implement the application?
The task is as follows: there is a coordinate base with checkpoints, these checkpoints are virtually attached to certain real coordinates (the application constantly monitors the location using GPS) and are on the ground, the player can see these checkpoints through the AR application and interact with them. How can this be implemented, how will it be better? Probably it will not be possible to place the checkpoint on the ground evenly, you will have to attach it, as I understand it, to a certain object that lies on the surface of the earth.