How do you install an aftermarket radio in a 2001 Alero?

Having attempted it more than one time on my 2002 Alero, I would say the short answer is "you don't"!

The door chime is part of the computer program in the radio, as is a few other timing functions of the vehicle. I believe there is an after-market kit to fix this problem, but it was way more expensive than a new radio, so I gave up. 70-2003 from metra and you lose door chime if a check engine light comes on you just have to put factory radio back in for tech to clear code... no "onstar" right? if so use Metra Electronics Corp. GMOS-01 or Metra Electronics Corp. GMOS-04...check your local car audio shops... big box stores usually have decent price equipment...but labor is crazy ...just go to a reputable local shop