[SonnyWortzik]

Start with the support backlog.

There is no better source of knowledge than solving software issues. You see it all in that backlog. Deployment issue, build issues, bug fixes, feature changes, merging problems, log files, web server configurations, DNS issues, certificate installations, database errors, database updates, connection issues, you name it. It is in there.

Once you feel comfortable with that backlog, look at the source code of your application and you will then ask your self, WHY IN THE WORLD WAS THIs BUILT THIS WAY?!?! you will find everything wrong with the application and that is a good feeling.

Start with Supporting an application before developing it.