The best way for me to explain that (and it will be different for everyone) is that I am aware of the line of the arrow. That is, from the nock end under my eye to the point of the arrow is in my peripheral vision and I know that it is lined up left and right with the target. No gap awareness for most shots out to 20/25 yards. The fact that I hadn't shot that bow for 20 years, took the two first arrows to get a feeling for elevation. After that it really was a matter of trust and focus (and I'd be lying if I didn't admit to a little luck :>) The big fight I had was really in the very different grip and not allowing that to influence the form execution.
The big reason for shooting the Black widow and the Bear at the end of that clip was to try to show that regardless of all the discussion about equipment setup. If your form is repeatable then any arrow with any bow will group. Yes spine, brace height, nocking point are important to actually hitting something but not necessarily for grouping. there's a difference.
And, By the way, There was NO nocking indicator on the Bear, I was just "eye balling" it