In order to view replay files (*.rpy) that people post in the forum areas, or that are included with setup files that can be downloaded elsewhere, save the .rpy files into your Documents / iRacing/ Replays folder.

Then log into members.iracing.com and go to Results & Stats...My Replays:



Then, on the replays tab, you have the choice of either Online Replays or Testing Replays:



and then click on the File Name of the replay you want to launch.