Are these courses really free ?

Yes, there's no upsell or anything, I made these courses because I genuinely want to help people who have a passion to learn piano and music but can't afford it. I spent a few years putting what I knew about piano and music theory into these in-depth courses. In real life you would pay thousands of dollars for this info spread over years of lessons.

Where should I start ?

If you don't have a piano yet, you can jump into the theory course right away, and it will still help in learning piano, but if you're excited to learn piano right away, you can jump into the piano course first. Either course can be learned in any order.