Hi, Keli! Welcome to TFP
As always Jason is right on the mark!! I would make a couple other suggestions:
You will need a good test kit, so go ahead and invest in Dave's kit found in my signature. We find that it is superior to other kits out there.
Use Jason's calculator to help you calculate the amount of bleach you need to add to your pool. Later, the other calculators for pH, TA, etc. will be helpful.
The more you test and add bleach, the faster your conversion will go. If you can only add once a day, do so at night. If you can do it 2 or 3 times a day or even more, it will go faster.
You will need to backwash or clean your filter frequently during this time. Filter your water 24/7 during this process, and keep a sharp eye on your pressure gauge.
When you think your conversion is over, post back and we can help you balance your water.
If you have any questions along the way, feel free to ask!!