How do i drive manual on G35 Sedan 2003?

Hey just stop the car put it in manule start driving and every time the rpm get to about 4000 push the gear lever up to the next gean. And when slowing down doo the opposite when the rpm gets under 3000 shft down simple ( you don't have to let off the gas) and when your on the high way going a stedy speed u can save gas buy shifting up 1 gear. Soo say if you are doing 50 in 4th gear you can save gas buy shifting to 5th gear the rpm will go lower and saw gas the car is smart if u don't shift up or down it will do it on it's own u cann only shift up extra 2 gears and down 2 extra gears