The Flat Top Kabuki Brush can be considered as a universal type of brush, as you can apply foundation, blush, cream, contour, and highlight with just this one brush. Also (as with any other kind of brush), there are more ways than one to use it.
As for which technique is best to use, it's recommended to try out each different way to see which works best for makeup application on your skin.
How to Use the Flat Top Kabuki Brush
1) "Spritz" the brush a little (so it is just a little damp) just before use. Some people like rose water or ELF mist, but regular tap water is fine as well.
Dab a small nickel size amount of the liquid product (such as foundation), onto the back of your non-dominant hand (or the hand that won't be holding the brush). If you prefer, you can use a palette instead. It's recommended to use the back of your hand as it warms the foundation and mixes with the natural oils of your skin, allowing for easier application.
Another way to apply is to dab the liquid product onto your face first using your fingers.
If using powder foundation, dab the brush gently into the product a few times, just enough to thinly cover the bristles, and tap off the excess.
2) Using the same quick and gentle dabbing motion, dab the product evenly and thinly from the bristles of the brush onto your face. Many people like to start from the center of their face (the nose) and work outwards (hairline, ears, neck).
Many people like to start from the center of their face (the nose) and work outwards (hairline, ears, neck).
3) Repeat step 2 until you've achieved the coverage desired.