Sorry guys, i've read dozen of things but it seems to me a little bit confusing.

what exactly do i need to craft a red dragonscale armor ?

i've read somewhere that you need a 'shard of the red dragon'
where i can find that one ? in the vault of the night raid ?

well i made thousand of runs without findind it, maybe i wrong something ?

so the ingredients are : 20 flawless red scales, the shard of the red dragon.. and.. ?

and then.. ? what else i need ?

pls help