Change structure of posts when plugin is used as widget

Hello,

Kindly could you please help me editing structure how posts are displayed in widget area.

Structure i need is thumbnail, title. I tried to do some changes but i guess i wasn’t editing right file.
I built a html form as example above widget. As reference you may check
This link

Thank you for your support and your time.

EB

https://www.ads-software.com/plugins/list-category-posts/