This video shows you how to make a carpet stain remover, a terrible carpet stain remover. Please I beg of you, don't use this DIY stain remover. They have basically made a combination of two ingredients that can both damage your carpet and guarantee that you will have a new stain to clean up in about two weeks.
I'm a professional carpet cleaner in Tampa FL and I deal with a lot of different stain removers. I can tell you that hydrogen peroxide is basically a form of bleach and I seldom recommend using it without some training on how to use responsibly. a tablespoon of dish soap has so many surfactants in it that it will attract dirt like a magnet attracts metal. I never recommend more than half a teaspoon of dish soap in any cleaning solution, and only if there is a cup or two of water in the recipe to help thin it out.
All the magical hand waving in the world will not make this a better carpet stain remover. These two ingredients at these concentrations is overkill, extreme overkill. You'll get the stain out and probably bleach your carpet and have a larger stain to deal with down the road as the soap attracts a whole new level of soil to the cleaned area.
If you need to know how to make a carpet stain remover I would suggest mixing 1/2 cup of vinegar, 1/2 cup of water, and 3 to 5 drops of dish soap together. Apply this solution to the stain and blot it up with a clean white towel. Because there is soap in this mixture, make sure to rinse it well with plain water to make all the soap is removed or it will create a new stain soon after.