TRACK Question

I've downloaded a few track designs from the RCT3 Ride exchange. The problem I am facing is that I dont quite know how to load them onto the game. I've placed them in the appropriate files, but then realized that the files are .tks. And all of the other files in the game folders are .ovl. Why is this? How can I load these tracks into my game? Thanks.

got to your mydocuments folder and go to the rct3 folder inside the my documents then click on the coaster folder and put all your tracks in there, and viola, they will be in the game when you use the prebuilts.