It doesn’t work. 
The pawn BluePrint:
http://puu.sh/9ZmSA/a0c77e2e8c.png
The BP_Waypoint (I named it Checkpoint):
http://puu.sh/9Zn7y/ca626179ed.png
The HUD:
http://puu.sh/9ZnkQ/69413eace8.png
The Set Active Waypoint function:
http://puu.sh/9Zny7/188811c89b.png
The BP_Waypoint Components:
http://puu.sh/9ZnGu/76b14f62ca.jpg