The path_corners are just the waypoint's man (like in a racing car game :D) Inside them, you put where to go next ("Next Stop Target", the name of the next path_corner).
The func_train is just the brush like a train, you set speed, algles etc. You NEED to put the first point (the name of the fist path_corner in the key: "First Stop Target")
If this is your questiom.. very simple