The instructions are all in Japanese but here's a good video that'll walk you through most of the basics:
https://youtu.be/nlmDYah5UsU
The online FSM will have all the torque specs, just scroll down and pick your year:
Nissan 370Z Factory Service Manuals
Lastly, here's the blueprint that came with the kit. Notice the 80mm height measurement for the rear spring adapter. You'll use the factory rubber upper/lower if your kit is the same as mine. At first I thought it would be way high and lowered the collar substantially. Big mistake. I didn't realize the lower rubber OEM isolator rotates and sits in a "groove" so to speak. So it was sitting far higher than it should. The measurements there are correct for their recommended height and it takes the worry out of trying to figure out the right height for everything:
The specs for the 370Z kit are slightly different from the G37 kit but I'd imagine the rear shock free length and spring height are identical. Same for the front. If you notice, they even says Z34 near the rear spring perch diagram.
Everything came assembled, and the fronts came assembled with the proper preload and everything. Springs have not sagged a mm since installation.