The section on setting your price is bad advice. There's no consideration for covering your business costs, your living costs, taxes, credit card processing costs, or even what the minimum wage rate is ($15/hr would actually be below the Australian minimum wage, for example).

There's lots of Freelance Rate Calculators out there that can give you better direction, here's a few selected semi-randomly:

https://motivapp.com/freelance-hourly-rate-calculator

http://www.flyingsolo.com.au/hourly-rate-calculator

https://hourlyrate.beewits.com/

There is one redeeming feature in the pricing suggestion (for beginners), and that is it might stop analysis paralysis. It's better to actually get out there & undersell yourself the first time, than to stress so much that you never even get your first client.