Checkpoint

I want to add a checkpoint to my minigame . It is like in Jump League with a touch on a gold block you save you spawnpoint there. Thanks for the answers . Can you say me please where i must add it and what is not correct on my plugin .??

Post your code where it faild and no one want to download a file and see whats the problem is , Tell us
1. WHAT is the problem
2.WHERE comes the problem

He doesn't have a problem... He just wants us to add checkpoints and check the code

What I would do is that create a new .yml file where it stores the player who have arrived at the checkpoint and teleports them back to the checkpoint if they are in that list.