As stated by
@V___25 you need liquid chlorine (LC) to raise your FC level to 8-10ppm. Buy 10 gals to get you started and stay away from pucks as well for now. Focus on that and you will see the pool start to clear. Both Walmart and Home Depot have pool sections where there should be liquid chlorine. Sometimes it is noted as liquid shock. I would suggest to stay away from granular shock as you get the best bang for the buck with liquid chlorine.
Also, have a little patience with using LC. It mixes quickly but does take time to raise the FC level that you need.
If you do plan to drain then do that first as you just waste LC. However, I think you can avoid that and just focus on raising LC. It would be good to get that test kit so you can ensure you maintain at the 8-10ppm. If you bring your pool sample to Leslie with a FC of 8ppm they will try to sell something to clear your water and say let your FC level drop to 4. That is a round robin you do not want to get into as they do not understand the FC/CYA relationship. The TFP methodology works for thousands of people. Give it a try but you can not mix TFP recommendations with pool store recommendations as they are in conflict with one another.