Google it. A search for "Scott Genius Setup" found a guide in this manual:
scottusa.com/downloads/genius_shock.pdf
The section "Setting up the Positive Spring" has 2 charts, 1 for +ve pressure (piggyback chamber), 1 for -ve pressure (main chamber). It has figures for rider weights up to 95kg.
You need to follow the instructions to the letter - doing positive first, then negative. Remember to make sure the Tracloc lever is in the Open position. I also empty the negative chamber before I make any changes (same as what I do with Rockshox Dual Air fork).
Then tune your rebound to suit personal preferences.
Good luck.