Let's take for example the Emulator I VST.
There are 3 folders inside the zip: Mac AU, VST2 and VST3.
VST2 and VST3 are in 64 bits, I abandoned the 32 bits support since it was pretty unstable.
Take the version you want to use: VST2 or VST3. Copy and paste it in your VST folder.
In default systems, it should be something like "C:\Program Files\VSTPlugIns"
Now run again your DAW: the VST should appear!
Let's take for example the Emulator I VST.
There are 3 folders inside the zip: Mac AU, VST2 and VST3.
Take the Mac AU folder. Go to "~/Library/Audio/Plug-Ins/Components"
Inside the Mac AU folder, copy the folder called Emulator I.component (Or whatever the name, XXX.component)
Just paste it in the "~/Library/Audio/Plug-Ins/Components" folder.
Go to "~/Library/Audio/Presets/" and there, paste the Presets folder contained in the Emulator I folder.
Now run again your DAW: it should work!
As simple as that ;D