Modified theme not applied on deploy

I made modifications to the minima theme and it works fine locally. However, when I deployed it, the basic minima theme was used and my modifications weren’t applied.

Do I need to publish my own theme to use my modifications?

I’m a beginner by the way.

is there a repo to look at?

How did you modify it? by creating the theme files in the layouts/includes folder in the root of your site?