I need help with TwentyTen theme and author settings

I recently started using WP and I like it. I know some CSS so I have created a child theme with custom css, and that works just fine.

But on my posts where there are links to the author (e.g., “posted by …”), the link results in a page not found error, because author page has been set up.

I looked at all the WP documentation here and the support forums, but nothing I have seen and tried works.

I also found one support thread on child themes and php, but the advice given there (i.e., simply copy php files like functions.php across to child theme and make your changes there) doesn’t work either. When I do that, my site loads and at the very top I see several lines of strings and codes from the functions.php file.

So, since the actual coding used in WP php files is absolutely Greek to me, I seek simple, easy-to-follow advice that is actually truthful (unlike the stuff I found in the forum I mentioned, where the advice given was clearly incomplete or outright wrong).

– I want the various author links in the Twenty Ten theme to lead to an actual author page, e.g., my profile.

– I want to know a method that allows me to make those changes in a way that is permanent, i.e., I don’t want them to be erased every time a new theme update comes along.

How do I do this and please don’t tell me to simply “copy across” the php files I need changed to my child theme, because that does not work. Or maybe it does, but it may require some extra changes to the functions.php after copying it to the child theme, but that’s not what the guy in that support forum wrote. According to him, and few others who seemed to agree with him, there was no need to add or change anything in the functions.php except the changes you want to make. Clearly that’s not true.