In 21K gallons, each 1.5 gallons of 6% bleach will raise your FC by just over 4 ppm. Until you have stabilizer in the pool, you'll need to keep a chlorine level of at least 1-3 ppm at all times. This will require 2 or 3 bleach additions daily, since the sun will consume much of your chlorine. You also need some stabilizer, also called CYA, and sometimes labeled as conditioner or balancer. You'll need to add enough to target about 40 ppm of CYA in your pool--either added through the skimmer and then filter not backwashed for a week to give it time to dissolve, or put into an old sock and tied in front of a return. It can take up to 4 or 5 days to dissolve, so don't test for it for at least that length of time--save your reagent. Once the stabilizer is dissolved in your pool water, then you can probably go to once daily bleach additions.

You can swim while this is dissolving--as long as you don't let your chlorine drop below 1 ppm, you can swim. Your pH is perfect, and your alk is fine. Don't let them sell you calcium, phosphate remover, or any algaecide other than polyquat 60--and you really don't even need that, except if you plan to close it for the winter.

There are other methods of chlorination--granular chlorine comes as cal-hypo (fine to use as long as your calcium doesn't get above 300 or so, then you have milky, cloudy water issues) or dichlor (fine to use as long as you realize it drives pH downward and raises CYA quickly, so watch for that if you use it).

When you get a chance, read as much of the info as you can at our sister site, PoolSolutions, and we're here if you have questions or problems. Congrats on the new pool!!

Edit: I see Carl and I were typing at the same time, but he was quicker to the "post" button. Note that the advice is the same!!