I'm pretty sure granulated and powder are about the same thing. Doesn't matter, it's crumbly. CYA doesn't really come in puck form, but chlorine does, it's called tri-chlor and these pucks contain CYA. Apparently the CYA is a binding agent of sorts so that chlorine gas can be stabilized in a solid form. Chlorine gas suspended in water is liquid chlorine (bleach).
Don't do anything till you test it with your new kit. When you add cya, if you use the pool calculator it will be accurate. So whatever ppm CYA you add, go ahead and use that number in the calculator. If you see over .5ppm of combined chlorine from the test tonight, shock (to assumed CYA level, squish the sock for a few hours tonight). If you don't have combined chlorine, just add bleach to hit target. Check tomorrow morning before the sun comes up, if you have lost less than 1ppm FC you're good to go. Again, no need to shock.
You'll want to test and adjust ph if needed as well. Probably before you do anything else except add the CYA.