There is no general rule about how much herbs to use.
Most recipes specify an amount in the list of ingredients. If you don't have a recipe to follow, start with 1/4 teaspoon and add more as needed to reach your ideal flavor. You don't want the herbs to overpower the other flavors in the dish. Dried herbs are stronger than fresh herbs so you will need to use more of the fresh herbs. If the recipe calls for 1 teaspoon of dried,...