Classic So what happened in BfA?

I'm not playing wow (mmorpg is just not my thing), however I've been huge fan of Warcraft universe since wc3 and i really like it's lore. Every expansion I'm surfing YouTube and trying to keep up, however I don't get the last one due to time lack. Any chance some of you give me quick explanation of what happened over all, what Sylvanas did and why? She was always my second favourite character, I had goosebumps from her "For the Horde!" in BfA cinematic and now i hear unbelievable "The Horde is nothing!" it just blew my mind. Also really interested in old gods so if anything I'd like to hear something new. From what I've heard there was something connected to N'Zoth and Azshara and that's all via /r/wow https://ift.tt/2mU65na