ok, yeah i think your kinda messing it up a bit, but take your time, you dont need to rush. You can add it any where you want. Its your story. If it fits perfectly after the first scene, then do it.
Hmm, it’s really up to you. But I use narratation when the character is deep in thought, or whenever something major happens. I suggest you don’t rush it though, it will come when it feels right eventually.