You are on the right track, Jane. Online safety is what you need to know and do to stay safe while working on the internet, or using social media.
But is it not safe to just stay on known sites and only talk to your friends?
Unfortunately, that is only part of it. You should also know to never give out personal detail about yourself to others. Never sign-up to sights that an adult have not approved as being safe. You should also make sure to never open e-mails from unknown origin, it might be a scam.
What if we come across a site and we don't know if it is safe?
You are correct, that would be the smart thing to do.
I think the best thing to will be to call the teacher or your parents before you continue.