Hello, I wanted to ask you where can I edit the sidebar. Thank you.
https://i.imgbox.com/74zXagfa.jpg (https://i.imgbox.com/74zXagfa.jpg)
Of course. All edits can be done in the theme.php and style.css files etc in your chosen theme. For more detail please post exactly what you want to adjust and a link to your site so we can advise more accurately.
Thank you and where can I find the theme.php and style.css ?
Please read the docs, they explain all in detail - http://documentation.coppermine-gallery.net/en/theme.htm#theme_files