If im using Rusk Thermal Str8 to straighten my hair with a flat iron. how should i use it?

im wondering if i should spray it on my hair by sections. all at once. or after im done striaghtening it. i have noo clue:/If im using Rusk Thermal Str8 to straighten my hair with a flat iron. how should i use it?
The way that I use mine is by spraying my hair all at once, then brushing it, then straightening my hair; I use it this way so that my hair is not wet when I straighten it.If im using Rusk Thermal Str8 to straighten my hair with a flat iron. how should i use it?
For straightening hair at home, you can use a hair iron and a straightening shampoo will also help. If you wish to straighten for a longer time, you can undergo Japanese hair straightening. I found this website useful - http://hcr.in/straighten.html