Add Slider to Category Page

Im trying to install a slider (“pointelle” if it matters) to each category page of my site. I’m using the telegraph theme by wpzoom and it doesn’t seem to have a category.php file.

How would I go about doing this? Do I need to create a category.php file? I’m new to WordPress and am completely lost. Also is this something I’d need to do in the child theme?

Thanks!