If you are going to fry something in a pan, give the pan a few good sprays of FryLight, heat it up, and go ahead as if you were shallow frying with oil.
You shouldn't really spray it into a hot pan, and be careful not to spray it near a gas flame/hot electric element!
For something you are doing in the oven, like roasted vegetables or roast potatoes, then spray your roasting dish, put in the vegetables/potatoes, and spray over them.
It is also very useful for greasing a pan if you are making a cake. Also, I spray the inside of my slow cooker dish before adding the ingredients as it helps to stop things sticking and makes the washing up easier.
It really is a useful product, and once you get the hang of it you will wonder how you ever did without it!!