So I installed the diesel fuel filter kits dual filter kit. I cut the very top fuel line to splice into is that correct??

Secondly, I’m using the fleece performance fuel filter delete, my question for this is I have 4 lines that goto the filter housing, two on the rear with the rear head return and one on the front, and one on the bottom. How do I re route these lines. It seems as is if the “supply” line they tell you to cut and splice the kit into is the return line. And the supply line in the lower of the two located on the rear of the factor housing. I am so utterly confused I need help LOL