That generic diagram shows a pressure line from the compressor housing on a turbo going to the input side of the air pressure regulator. That is boost pressure from the compressor housing and the air pressure there is the same as air pressure in the pressure line coming off the inlet side end tank of your intercooler. The 911 turbo takes it from the inlet side end tank of the the intercooler.
The way it works is simple for me to understand. I know how an air pressure regulator works and I can't explain how to hook up an air presure regulator type boost controller any better than this diagram. The 935 boost controller is an air pressure regulator... a very nice working and nice looking fancy old German one that is a valuable collector item these days.
This is the inexpensive generic one I have but it works the same way as your 935 boost controller and it makes no difference what turbocharged car you install and use it on.
Turbonetics Manual Boost Controller Toyota Civic Honda Chevy Ford Subaru BRZ | eBay