How to use auto pilot in the boeings

[BoredPilot]

I want the auto pilot the fly the route i put in route manager.

[wkitty42]

which route manager? some craft use their own route manager instead of the default one available in the F10 menu... there should be a manual or tutorial in the craft or its installation directory... if not, you might find one by asking uncle google... that is if the craft is simulated accurately

[flycanarias]

Well, when you activated the route in the built in FG route manager, activate the AP and activate the LNAV button. The aircraft will follow the route now.
Usually, you find the LNAV switch near the HDG selector.