Question: Sterling JP157 Pickup Change and Wiring questions.

For about a year, I’ve owned a Sterling JP157 7 string guitar and I’ve decided to put in Dimarzio Titan pickups in. I have a 3 way switch, 1 push/push with a 12dB volume boost, and a tone knob. I read that I could rewire the volume push/push knob to become a coil tap to split my humbuckers. I was hoping that I could receive guidance to do so? (Wiring diagrams, etc)