Q: Where to put vst3 files?
Ans : C:\Program Files\Common Files\VST3\RDGAudio
Q: Where to put user preset files (.rdg files)?
C:\Users\Username\AppData\Roaming\RDGAudio\SawPluck\User Presets\Factory
For Mac :
….\Library\Audio\Plug-Ins\Components
….\Library\Audio\Plug-Ins\VST3
Watch the installation guide.