Rct3 Platinum Buildings How Do I Input Other People's Rides, New Or Old, Into RCT3 Platinum?

How do I input other people's rides, new or old, into RCT3 Platinum? - rct3 platinum buildings

I lost a little bit. I'm on a roller coaster that I download the RCT3 folder in My Documents, but I do not think so, while showing the game. Can you help me please?