VST Instrument Sets Explained, Solving Problems

Hi, thanks for your response. Following the link you gave me I’ve got at the moment everything downloaded in my Download folder as before. The difference is it is packed in one folder Steinberg/WIN64 etc. Still don’t know how to make it visible for Cubase.
Point 2 says about downloading and point 3 says about where I should find downloads. But I don’t.
Just to make it clear where I am:
Cubase 10.5 downloaded, installed and registered
VST4 downloaded - apps installed and registered, content downloaded and registered.
What should I do next, what to do with content in my Download folder? How to install it? Thank you