Just started playing Jayce and I'm a bit confused

Hi, I recently started playing Jayce top but I've seen many people saying he's better mid now.

I'm a mid main but was wondering in which lane I should play him, which runes to take and build path to follow. I've seen people saying manamune is 1st item and others saying it sucks. People saying you should go botrk and others saying sanguine. The overall consent is that lethality is good on him, Black cleaver and GA.

It would be very helpful if you could clarify these things for me, thanks!