Turn it on manual mode, go into settings and assign the record button to act as ISO button when you hold it down.
Use the normal shutter button, its close to your ISO button now.
The front command dial is shutter speed I think, the rear dial aperture and hold down record button and turn rear dial to control ISO.
If you use it like that it is the easiest camera I ever used to set iso, shutter and aperture with no auto functions.
You can do it single handed without moving your eye from the viewfinder.
I tell the back button to switch between crop mode because I use that sometimes.
Get a £20 aftermarket battery grip with a nipple controller thingy on the back perhaps, I think it makes it a better camera with a lot more controls.
Or if your going to use auto modes I have no idea because I never used them, I always forced myself to use manual mode.