[COD] How do I play this lowk

Yo I hope I don't get flamed for this, but like, COD looks cool asf and I wanna start playing it, but there's like SOOOOO many different games/versions/idontknow and I highkey don't know anything about this. Do I need to play all the games? Do I miss relevant lore if I don't play all of them? Which is the most important one that I should buy if I only wanna buy one? Which one do most people have? And mainly, what is it even about? All I caught was that there's like, missions, and stuff, but that's all I really know. Can you pvp other players idk

Yeah I don't know anything ngl pls don't eradicate me I just wanna find some cool games to play and COD looks sick asf