By using hardware, software, APIs, languages, technologies or features that are either no longer supported or have been superceded, typically combined with little to no possibility of ever replacing that code, instead using it til it or the system dies.
How many bugs have been introduced because of incorrectly written GOTOs? How much money did they cost the company? Turn the issue into something concrete, rather than “this feels bad”. Once you can get it recognized as a problem by the people in charge, turn it into a policy like, “no new GOTOs for anything … Read more
Start with some small task if possible, debug the code around your problem. Stepping through code in debug mode is the easiest way to learn how something works.