hi i get confused on how the VNAV and the Altitude button operates on the panel, i was experimenting and tried to climb to FL310 from the current FL290 but what buttons do i need to press for this to work?also once i take off the FMC is programmed to to cruise at FL290, however do i have the altitude set at 10000 feet, how do i get the aircraft to continue to FL290, cause it always levels of at 10000 feet, do i need to press VNAV, i have done that but it still stops at 10000 feetthx!

If you want to cruise at FL290 you need to set the altitude to 29,000 ft.

Altitude window got to be set at 29,000 feet if you are to cruise at FL 290. From FL 290 to 310, tune 31,000 feet in the altitude window and press the knob. Keep Lnav and Vnav on in this case. Step climbs can also be done by FLCH at a desired speed.