Not quite clear what you're asking. Have you researched finings? There are different types but if you're brewing kits or extracts then kettle finings are irrelevant.
Basically they operate to coagulate and therefore drop out matter from your wort or beer that may contribute to haze. This results in clearer beer.
The finings the HB shop sells are probably overpriced gelatin. A teaspoon of gelatin (bought much cheaper from the supermarket) dissolved in water between 70 and 90 degrees, allowed to cool to <50 degrees and added gently in will go a long way to making your beer clear sooner. Contrary to people telling you it is just cosmetic, what is being dropped out by that is yeast. Yeast has an impact on beer flavour so dropping out a lot of the yeast will have an impact on flavour (a positive one to my mind).
If you can combine gelatin additions with cooling the beer to between 2 and 4 degrees and letting it sit for a week, it will work better. Yeast will drop out purely with time as suggested but you will need to mature the beer in the fermenter until it clears. Finings speed things along a little and reduce the small likelihood of infection or oxidation in finished beer.
I've used finings and gelatin, to my mind an extra week or 2 in the fermenter will often do the same job but on the balance if speed is needed, gelatin in my mind is cheaper and has the same result.