TC=FC+CC or Total Chlorine = Free Chlorine + Combined Chlorine.

Free Chlorine is good
Combined Chlorine is bad (it is chlorine that is bound up trying to remove some contaminant)

You don't have to drain the pool to get rid of free chlorine.

You need to know if your pool has CYA or Cyanuric Acid (also called stabilizer) in it. You need some or you will have a hard time holding your free chlorine through a sunny day. You need to know how much so you know how much FC you need to maintain.

You will need to address you alkalinity issue, but just holding your pH near 7.2 will be all you need. Normally with high alkalinity, your pH will tend to climb, so you will have to add muriatic acid to keep it low enough.

You may have some testing issues since your chlorine numbers don't add up. I would take a sample to a pool store and see what kind of numbers they get. Don't listen to what they tell you to add.

Hang in there, you don't have any urgent issues, so you have time to learn how to handle it. It's not hard.