This is how this will go:
Get your taylor kit, and do pH, FC, TC, and CYA tests and post your numbers here. Probably don't need to really worry about TA and Calcium right now.
If the CYA is really high, like over 60 or 70, then yes you are better off draining SOME of the pool, so don't add anything but a gallon of bleach each day until then.
Assuming drain is not necessary, you will lower the ph to 7.2 or thereabouts. you will need muratic acid for this.
You will likely need the SLAM process, which means you raise the FC level to shock level and keep it there, as long as necessary to pass the three criteria.
Shock level depends on your CYA level. Reference the
FC/CYA chart in pool school.
This means testing and adding liquid chlorine throughout the day. And brushing the pool. You'll need to buy 10-12 gallons of liquid chlorine to start; regular old bleach works ok, but if you can get 8% or 10% it will mean fewer containers.
You will need to be home all day to do this, probably for a few days. If you do have ammonia, because the FC disappears in minutes, you will need much more bleach, but you WILL break it at some point and it will start to hold.
Look in the POOL SCHOOL tab at the top and start reading up on the
SLAM.