How to Show Full Posts (instead of thumbnails) when Clicking on a Category

When clicking on a category I would like for my blog to show a string of all the relevant posts with their full content, rather than a list with thumbnails and partial content… in other words, I want it to look as it does on the home page, but only the posts in the selected category. I am using the Gridline Theme from GraphPaper Press.
Anyone know how to do this and willing to guide me through it?
Thankyou!!!

(what I want) Home Page: https://patrickcavanbrown.com/blog

(what i have)Category: https://patrickcavanbrown.com/blog/category/stories/bull-fight/