Now that you've been introduced to the lights, it's about time to start adding them to your level. The general rule when lighting the level is to start with dominant lights (usually directional sunlight/moonlight) and continue in descending order. Don't try to tweak multiple lights at the same time, focus on one and then on another once you are satisfied. The more lights you add, the more color mixing will happen and you might find yourself in a situation of not being able to figure out what to tweak to get the desired effect.
If you wish to challenge yourself, try to bake some of the areas that your character will not be moving into and optimize lighting to the best of your ability.