Sorry, I don’t understand. The topic title is “config.php”, though WP does not have a file by that name. Otherwise, what editor are you referring to? What do you want to edit?
Note, though, that editing the theme is A Bad Idea as your edits will get wiped out when the theme is updated. As it’s a new theme, updates are likely. The solution is to use a child theme if you’re changing PHP, or use the Custom CSS feature of the customizer if you want to change CSS.