landing and gps

can any tell me how to line up straight with the runway and how to make the ATC tell u to descend and maitian and the heading. the gps system just lines up with like the center of the airport so i can't find the correct runway

can any one please help>?

See if this helps.

http://flyawaysimulation.com/postt8080.html

so if i am the like not straight and not heading in the right direction the autopilot will turn it for me? if i press apporach?

Affirmative.