Well, you can identify males by their GIANT "sack of jewels". It's rather unmistakable.
I'm guessing you have two rats of the same gender if their genitals look the same.
You don't have to do anything special.
Just put the male and females together and they will work their magic. Approximately 22 days after mating, you will get your first litter. And about 4-5 weeks after that, the litter should be fully weaned. They breed as often as you want them to.
If you keep the male with the females full time, the females can go into heat hours after giving birth. If this happens, the next litter will be born right after the previous litter is weaning.
Personally I like to give females breaks between litters, but that's really up to you.