When I use the setup guide to click "learn the basics of product formulas", it shows that I have no products.
That's because in your instance, There isn't a product with the ID of 1, this is probably because you tried one out and deleted it.
To make the tutorials work, we have to guess a product ID, and #1 is a pretty sure bet. What you CAN do is replace the ID in the URL bar with a product that does exist in your system.
For example, change this: