I would like to edit the theme TwentyTwelve on a few things:
1- Put a logo next to the written title;
2- Add the "author" item in the articles;
3- Remove the "Website" field from the comments.
Even though my knowledge of html and php is minimal, I managed to do these things on my own on some themes, but I've been told it's better to use this so called "child theme" to edit the themes, so that when these get updated, I won't lose any change I made.
So reading around the Internet, I haven't been able to fully understand how to use this child theme. I only managed to create a theme with the same CSS file of twentytwelve.
What I need to know is how to add changes to the main theme using the child theme (a practical example with one of the issues above would be awesome) and also how to add the logo manteining the responsiveness.
I've not got a blog online yet, I'm working on this theme locally.
I tried to be as much clear as possible, hopefully you can understand my english.
Here are some screenshots to explain better what I'm looking for: