Honestly, id just get a galon of water and slowly poor till I see it coming from the drainage holes on the bottom of your container. Thats when you know the soils fully saturated with water - take note of how much you use when you see that, and thats how much you should use until your plant starts to drink more!
As for how often, be sure you allow your soil to get pretty dry before watering again! I usually stick my finger in the soil near the edge of the container, if its dry down to a knuckle or more its time to water. You can also tell by the weight of the pot once you get a feel for it.
Letting the soil dry is important, helps the roots to get some air and also encourages them to grow more by making them search harder for water. Dont overdo it though, if your leaves start to wilt/curl then you waited too long. Usually I water once I see that I can put a finger in and no dirt really comes back with me when I pull it out. hope this helped!