Every gallon of 6% bleach will add about 2ppm of chlorine to your pool.
Every gallon of 12.5% Liquid Chlorine will add about 4ppm of chlorine to your pool.

Bleach and Liquid Chlorine are the same thing, only LC, when it's 12.5% strength, is twice as concentrated as bleach. It's what I use because, in my area, it's actually cheaper than bleach and the containers are reusable, but in other areas, bleach is cheaper.

You should add 5 gallons of bleach to your pool as it's filling and keep the chlorine level at at least 10ppm. Meanwhile, you'll need to watch your pH level (it should be between 7.2 and 7.8). You raise pH with 20 Mule Team Borax (you can use Washing Soda, but this raises "Total Alkalinity", good if you need to raise it, bad if you are already at the target level), and lower it with either Muriatic Acid or Dry Acid. You will also need to get some CYA (also called stabilizer) into your water. It acts to prevent rapid UV breakdown of chlorine. Start by hanging 2 lbs in an old sock or stocking near the return and plan on it taking 48 hours to a week to dissolve.

You need to get a proper test kit. We recommend the Taylor K-2006 and K-2006C. You can buy them by finding Watermom's or PoolDoc's posts and clicking on the link to test kits in their signature. Barring that, Leslies on-line sells their Chlorine FAS-DPD Service Test Kit, which is the K-2006 re-branded and a bit pricey. For the $50 to $70 it costs, it will pay you back 1000x over the years.

Carl