EDU theme (smooth themes) – need help to delete it

Hi, I am a beginner, a friend downloaded a theme (EDU) to my wordpress site from smooththemes https://themeforest.net/item/edu-educational-courses-college-wp-theme/5991392?WT.ac=search_item&WT.z_author=SmoothThemes and I cannot see anyway to delete it there’s no obvious delete button. I’ve tried activating another wordpress pre installed theme and it’s just mashed up with the EDU theme. Can anyone help:( Many thanks Jill