A very good afternoon from the UK !
love the RCT platinum edition , with soaked and wild .. would now like to add some custom scenery and lighting !

Welcome. I have RCT3 Platinum version as well. If you don't know where to get the custom scenery objects (cso), csutom scenery tracks (ctr)
or custom flat rides (cfr) you can find many of them here:

The Custom Scenery Depot
http://www.customscenerydepot.com/

RCT-3.org
http://www.rct-3.org/downloads/index.php...y/101-CSO/

and on this site as well.

I hope you will share your work and have lots of fun.