As said in one of the comments, this is really simple. Within your theme folder, you can create a file called category.php. Once in place, you can modify to your hearts content without the need to do anything fancy such as redirection. If you want to target a specific category, let's say music, then the file would be category-music.php
It's also worth noting, that if you're using a theme you did not develop, to create a child theme and put this file in that directory instead. You should never modify an existing themes files, including creating new files, because all your changes will be lost once you update the theme.