You water sufficiently when the plant needs it, until the excess runs out of the drainage holes. Once the top inch or two of the medium is dry and the pots have lightened, you do it again.
Nobody is going to be able to tell you exactly how much water to give- or when, all of this depends on you medium, container size, temperature and humidity, strain, etc. Larger containers are generally watered less frequently. Smaller containers tend to need water more frequently.
After you transplant into a larger container you can water less frequently, then as the root system grows you'll eventually have to water more frequently. During the last couple weeks of flowering plants use less water, therefore you can water less frequently (which will also help prevent botrytis).