If you want to find a really good course, I can advise this company - CapitalXP
Here you and the demo bill will open and will teach and help.
You can check this company by reading the returns on it - https://capital-xpreview.com/
Bitcoin.com is just one domain name used to promote Bitcoin. Bitcoin.com is not an official website. Just like nobody owns the email technology, nobody owns the Bitcoin network.
As such, nobody can speak with authority in the name of Bitcoin.