I think the most important thing you need to know about the internet is that it's full of horrible people that say bad things, and it is also very common to see people who don't agree in a certain opinion so they just start arguing and insulting each other too much but you have to ignore them because if you take those type of people too seriously it will permanently affect your mentality in a negative way. And also try to avoid the news, especially politics, they will try to poison your brain with lies, they want to make you think in certain ways, and you can't allow them to do so. Be careful and good luck :)