I see all this great content like new rides and scenery but I can not figure out how to add the content. For example I saw that there was a Windseeker ride but I could not figure out what folder to put it in? Anyone with a mac want to chime in and help me with this issue?

Maybe this helps:
https://www.youtube.com/watch?v=2T7jg5PH7FI

Somewhere here in the forum should be some threads from Mac-Users with install questions.
There could be some infos/links for CS's install, too.

Lg Cheleste

What you can do is simply search up in your spotlight (the magnify glass on the top right hand corner of the screen) "Themed", It should give you some options, then simply click you the top result and it should give you the folder to put them in. Also, have you purchased RCT3 Platinum through the mac app store or are you running it a different way.

i also have it on a mac, for custom flat rides, go to programs, right click rct3 and click on show package content, gamedata, style, make a folder named "custom" and drag the flat ride in that folder (without readme). for cs do the same but if you are in the style folder, drag it into themed