It is fine to use the 12.5% chlorine. It is the same as bleach, only stronger. (Bleach is 6% sodium hypochlorite.) After you get a few feet of water in the pool, go ahead and start drizzling a little chlorine in there and stir it around with a clean broom or something. Continue to do so after another couple of feet. Be careful not to splash any on yourself or the liner.)
After the pool is full and you start the pump, you can make any adjustments to pH that you need. (Test your fill water tomorrow and post results.)
You'll have to decide if you want to just add stabilizer separately to get to about 40ppm or add some separately to get to a lower level and then use some of the pucks to get the rest of the way to your target level. Most people like 40-50ppm of CYA.
Post test results tomorrow and also decide how you want to add the CYA and somebody here can take you from there.
EDIT --- Also, we need to know what type of pool this is, and its volume. Also, what type of filter and size of pump you have.