How to replace a carburator on a Snapper SR1028 ?

I have a Snapper SR1028 with a Briggs & Stratton engine Model=28A707, Type =0122-02 that is not starting. Mower was not used for more than three seasons. Was told needed a new carburetor, which I located on the net as Part# 498027 (replaces 499161). Since this is an expensive part (~$135) I am trying to install myself. I am looking for advice on how to install this correctly (and set the choke) and/or a link to engine repair manual on how to install the new carb. I am not sure on how or if I can rebuild the old one. Thank you very much in advance for your advice and help.

moses
June 2010