How do I customize the source code of my theme? I'd like to make some changes

I’m familiar with Shopify themes and their liquid programming language. How do I make changes to the source code of the theme for my store?

The first thing you’ll want to do is install your theme to your site by opening your dashboard > choose Theme in the side menu > click Add theme button at the top > Install theme… and then upload the zip.

This will install the theme into your store and from there you can make changes and upload revisions by clicking on the arrow next to “Customize theme” and choose Upload revision…

That will make your changes available as a new draft that you can preview or publish and make active on the site.