Hey, sorry for the late response. I apply it with my fingers, I put some starch on my index finger and thumb and then just apply it on strands, starting from the base and moving to the tip, then I comb through the hair. Be careful not to apply too much at a time, just do it in slow steps.

@dino-saur I found about this when reading about natural dry shampoos. there is an option to add cocoa powder to the corn starch for darker hair as this really puts an ash tone to the hair.
I don't know how freequently you'd have to apply this as I only do it on my last day.