The Zex "Nitrous Management Unit" (NMU for short) goes inline with the hose coming off the fuel pressure regulator (FPR for short).
Pull the hose off the FPR, but not the other connection.
Run a length of the included hose from the FPR to the NMU connector labeled "Regulator".
Then run another length of hose from the NMU connector labeled "Intake" to where the other side of the original hose is still connected (I think it a T connector).
It should go like this;
FPR---------->NMU---------->Intake Manifold
