1.Unplug all power and data cables, PSU and all drives and fans.
2. Install PSU (put cable into socket but do not turn PSU on(this is just a grounding technique)), fans and all drives in new case.
3.Work out where your motherboard mount holes are and make quick measurements and a quick sketch on paper where they are. Then put paper on new case and screw on motherboard mounts that correspond to it.
4.Unscrew GPU and any other PCI cards and put on anti static surface.
5.Unscrew motherboard mounts while case is on its side. Then put motherboard (including cpu, cooler and ram installed) on anti static surface.
6. Remove I.O shied and install in new case.
7. Install and screw in motherboard to new case mounts.
8. Re-install GPU and other...