First of all, you can ignore the bromine side of the tester. You don't have bromine -- this is a chlorine pool.

You need to get a better test kit. We recommend the Taylor K-2006 or 2006C which you can pick up at a good price from the testkit link in my signature below. (You can't buy it locally.)

With your tester, since you are hitting the limits on the range that it can read, you really don't know if your chlorine is 11 or 20, only that it is higher than 10. Until you can get the good kit, you can force your kit to read higher with a dilution method. It isn't very accurate and isn't meant to replace getting a good kit, but it is better than nothing. Read more about it here: Testing Without a Good Kit

What have you used to shock with? We need ingredients -- not just "shock."

Again, with your kit, your pH may actually be much lower than 6.8 since there is no way to differentiate lower than that. You need to get the pH above 7.0 ASAP because any reading below 7.0 is acidic and can damage your pool. However, you need to test the pH when the chlorine reading is no higher than 5 or you won't get an accurate reading. You can raise pH by using 20 Mule Team Borax (laundry aisle at Walmart.) Start with a half a box added slowly to the skimmer while the pump was running, breaking up any clumps. After a couple of hours, retest and redose until you get the pH above 7.0. This is pretty critical so you need to do this ASAP.

Hope this helps you get started. Come back if you have further questions and ...... order the good kit as soon as possible. You need it.

EDIT -- I just noticed that you said you had test strips or "guess strips" as we call them. They aren't reliable. You need a good kit as I mentioned above, but in the meantime, pick up a cheap OTO/Phenol Red kit (yellow and red drops) or if you can find it, some Walmarts have a HTH 6-Way kit that will suffice for now. Also, get some distilled water while you are there. You'll need it for the dilution test.