Whenever the answer to a Drupal question, either here or on blogs and other articles, is to use a hook and then some example code is provided, what are the assumed steps from beginning to end for implementing this answer? These are likely left out to avoid redundancy but it's difficult to piece together the underlying, assumed foundation and skills.
Where does the given example code from many such answers to questions go? Is this essentially what building a module is? The concept of a hook is easy to understand and explained well here but how to use a specific hook to alter some piece of core to achieve something isn't clear.
For example, if the question is, "how do I change the text of such and such button" and the answer is "use hook
hook_such_and_such_blahdy_blah" what does this actually mean?
Real world example: This blog about how to theme the comment block is great. But what is the author really saying to do when he says to just override the hook by copying the code from the API page and then alter the hook.
Resources I've checked out but don't mean anything without the missing foundation: