Blog Template

Hello, I want to remove the side bar from my blog posts. I was told by someone to edit the template-blog.php. But I have not idea what to do after that.

Also i have been trying to change the copyright section on my website for the longest time. It seems like its set up so it can’t be changed. I’ve asked this question and followed the directions, but the changes never went though on the website itself. Any help would be appreciated.