The author has some serious design and coding skills. I just wish they were more precise about what it is (a window manager? an gnome user theme?) rather than trying to brand it as a javascript-based operating system.
I do a lot of work helping early and mid-stage companies scale their workforce and technology. Some companies scale by the seat of their pants: they hire people for specific needs as they arise (e.g. servers crashing, or too many sales requests coming in). Other companies scale in a more organized, planned process, like having a big vision of becoming a global company in 5 years. In both of these scenarios, especially because you don't have a co-founder, you're going to find that it's hard to give your #2 hire a sense of agency. You'll likely feel disappointed in their style (different coding practices, different customer interactions, etc.) and want to micromanage. To help with this, start them off on a non-mission-critical project (like expanding to a new region or building a feature that's been in the backlog), and be clear with them about what "success" means for that project. Having the definition of success be written by them, in their words, will also help ensure a two-way communication here. After they have a successful project under their belt, you'll find it easier to trust them with more important work. Also keep in mind that right now you have a product, but when you hire your second employee, you'll also be establishing a culture, so it's worth putting thought into what culture you want to promote.
Markov chains are much simpler than Markov models. The lecture starts off with the simpler idea to motivate the more complex one that you're describing.