More information please, with regard to what you see as complex.

You should be able to knock off the retainer clips, and then drift out the
hinge pins.  The door will then simply come right off.

You'll want to replace the brass bushings when putting the new door on so
pay attention to how they go on before removing the old door.  They are
commonly available at most automotive aftermarket stores.

The coil spring in there will give you some anxious moments and may even
give rise to some new words in your vocabulary.  I generally place it in a
vise and compress it completely.  Then I wrap a coat hanger through the
center of it and around the coils to keep them compressed.  Try to keep it
evenly wrapped so that the coil does not uncompress on one side when you
remove it from the vise.  You can then insert it into the mounts and you
will likely have to give it a pry with a large screw driver or the likes to
get it partially seated.  That is the part that usually gives you some
trouble.  Once you've got it seated, or what appears to be seated enough,
cut the coat hanger to release the spring.  Swearing during this process is
not considered a sin or a lapse in social grace.