Hi @restive! Like @qubicrm pointed out, I am in the process of writing down my notes about creating Salt formulas (and installing them).
The progess is tracked in this forum post where I’d be happy to discuss what may be useful to you.
I finished writing a tutorial about writing a Salt state (no pillar) a couple of days ago, and the guide on formulas (state + pillar) will take some time, but the docs that @qubicrm linked already contain links to example code that you may find useful.
Again, I am happy to help answering questions in the meantime, either in this forum (if the questions are specific to using Salt in Qubes OS) or in the discussions section of the GitHub repository that contains the code examples if the questions are more about Salt than Qubes OS. 