New water: FC and TC = 6ppm, no CYA yet...
No need to shock. You should have gotten FC of 7.8ppm, but it must have metabolized something--and no CC measured. That's good.

I don't quite know how to compute the amount of CYA 1 puck will add to a pool. What I would do is use pucks (if you must) in a floater and measure CYA weekly, at a minimum. When it passes 30ppm, stop.

Or you can buy CYA directly. Figure, from the package, how much you need to reach your target in your pool, then use 1/4 to 1/2 what you computed. Add it and wait a week to test CYA. (use the rules on putting it in a sock, or in the skimmer and not backwashing--search the forum).

Alk: I like to add 1lb via the skimmer, wait a day, test, and add another pound, and keep it up until TA passes 100. 150 is FINE in a vinyl pool--I like 180 to be my max before I take action to lower it ...Concrete pool owners--your max is 125.

But overall, I think your pool is looking terrific and you are doing everything right to start off with healthy water! Well Done!