Hi! Welcome to this forum!
You will have to spend some time reading other's mods here because there is just too much to explain. And only you know the final result you want to have. You'll need to decide if you want to cut the case or not, if you modify your power supply for the original casing or if you relocate it,if you use the original front panel or not...
Those are just the start, you have a couple of hours of reading here.