I need a beginner's guide to fandoms for my friend!

So I've been in the Percy Jackson fandom for a while now, and my friend "joined" just this summer. She has BREEZED through the books, and she's on MOA now. Seems like she's officially joined the fandom, right? WRONG. She knows about the stuff written in the books, just not.. Internet related stuff and fangirling like a true fangirl. FANGIRLING IS SRS BSSNSS. I emailed her this headcannon I saw on instagram about Percy dying, and she flipped out. Not just like, having a fangirl mental breakdown flipped out, no, she took it like Rick Riordan HIMSELF put that in the books. She is as of right now, spamming me with texts saying "NOOOOOOOOOOOOOOO THERE HAS TO BE A WAY TO KEEP PERCY ALIVE NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO HULDHSAULFDHSAU NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO" etc. I also think she might be trying to one up me, but she rarely goes on the internet. Doesn't even know what OTP stands for! So my main question: Can you make a guide to fangirling and fandoms for my friend? If not, please tell me what to do and give me the words to say it. feel free to ask perguntas at any time.

Thank u
XOXO, K