That manual is the most worthless POS I've ever seen.
DO NOT set your CG with fuel in the tank or you'll be very tail heavy at the end of a flight.
If you don't own a CG Machine or know someone who does. Here is an easy way to get a decent and safe CG setting for your first few flights until you think you might need more balance towards the tail.

Start out with an EMPTY FUEL TANK.
Plane upside down or rightside up. (Doesn't matter as much with a mid-wing acrobat like an Edge540 or in this case,,, SS120. I balance my mid-winged planes rightside up.
Feel along the wing for the main spar that runs from the root to the tip. Place your index finger on or just ahead of the spar closest to the fuse and lift your plane. Move rx gear or add weight so that it balances or slightly falls forward towards the nose.
Better to maiden nose heavy than tail heavy any day.