D.W.
I use Arm & Hammer Essentials Free and Clear. It's one of the highly recommended for cloth and easily found. You only use a tablespoon or so for an entire load so a bottle lasts a long time! Be wary of using bleach for every wash. Bleach destroys your diapers and makes them wear out faster. I use bleach maybe once a month or so but that's it.
I believe the site is diaperjungle.com that has a list of diaper detergents and their ratings.
You will want to do a cold wash/rinse with no detergent, hot wash with the touch of detergent/hot rinse (if you have it. my washer will only do cold rinse) and then a final hot wash/rinse cycle.
You will also need to prep your diapers if you bought prefolds. They have to be prepped correctly or they won't absorb/work well.