How do you take out a car's door lock?

Yup take the door panel off and then take the rod assembly off the back of the lock from the inside of the door, and on most cars a clip is all that actually holds in the lock its self. If the lock is part of a door handle assembly you may have to take the handle off too to get the lock out, but it is not hard to get out.

Be careful not to break clips or the door panel when taking it off they make special clip removal tools and they can be purchased fairly inexpensively at a parts store.

it really depends on the car u will need a Circe clip remover (if its manual windows)and a pry bar its not that hard to do most of the time just make shure u unscrew all the screws be for prying it off. there usually is one hidden under armrest. then the lock is held in bye a little plastic piece

Go to your local auto parts store and ask for a haynes manuel for the make and model of the vehicle. that book will have detailed information on your vehicle.