Needing help with Block where player is at

[Hello123456]

Hi, so I wanted to make a skript that basically teleports the player if they stand on a block at 15, 4, 63. I got down where to teleport the player but I dont know which event checks where the player is at. 

The code I am looking for is something like the line mentioned below

if player is at location(0, 0, 0, world "Example"):

Teleport them (I already got this part working)

Help would be appreciated. 

P.S. Tarna if you are reading this sry for the copious amount of posts on this one stupid teleport skript lol.