As Gonk mentioned, the instructions in the 970 manual should set out everything pretty clearly.

The only tips I would add are: First, make sure there is no extraneous noise in your listening environment while you're calibrating. Second, some guides recommend you put the SPL meter on a tripod, facing the ceiling. In reality, where you can effectively put the tripod may be 1-2 feet away from your listening sweet spot -- especially if your listening chair is a sofa.

I prefer to take a seat in the sweet spot, sitting notmally (not pitched forward) then hold the meter close to my face, that way you calibrate as close to your ears as possible.

Lastly, you may wind up recalibrating the LFE channel to personal taste. I've noticed to achieve the same SPL reading on the meter at the pink noise frequency, the sub output may be a bit too much during movie and music playback. A little manual tweaking on the sub's volume knob can bring it back into balance.

Good luck!