it's reversing, there is not an universal way to follow because there could be cases in which is needed to have other intuitions and reaching the code in other ways.
anyway if you don't know how to use a debugger (basic commands), x86 assembly, the most common windows api and so on then there is nothing to do.
and if you know them you already know what to do.
that's why there will be never a guide/tutorial/video from me except if it's something so easy that there are 90% of success.
at the moment the only thing I see that could fit this percentage is the retrieving of the password used to encrypt the zip files used in some games and for which I already wrote some steps in various posts of this thread:
http://forum.xentax.com/viewtopic.php?f=29&t=3662