You got start9 setup, that's def step in right direction 🔥. You can give your friends user accounts. After they have got the accounts disable making new accounts in server. I would also use a regular user account for yourself, it's more secure. Using super user account install extensions and just play around. They're fun
Most have a more button with videos and description so you can learn what the do. Good luck 🚀🚀🚀