* Connect a fuel-hose between the outlet of the stock FPR and the inlet of the adjustable FPR.
* Connect a fuel-hose between the outlet of the adjustable FPR and the fuel return-line.
* Cut the vacuum hose that connects to the stock FPR and put the T-junction in the middle.
* Connect a new vacuum hose between the T-junction and the vacuum inlet of the adjustable FPR.
* Secure all fuel hoses with hose clamps and make sure there are no leaks (you should be two persons for this, one operating the car and one looking at the connections).