Of course you’re allowed to learn from tutorials. The question about assets is covered in the Jam Rules under “Allowed.”
Viewing post in About the rules
The phrasing of the rule is abundantly clear: “You may not directly reference any real-world political or religious people, events, or idea.”
You’re skipping the most important part of the rule: “real world.”
Civilization - Uses real governments and leaders, therefore political, would be disqualified.
Super Mario Bros. - Okay. No one will be offended by a poor representation of Bowser as a leader.