If your hair is the color that it is in the avatar, it will only give undertones. You might wanna lighten it first. But you do 1 pack per 1/4 cup of shampoo let it sit for 10-20 minutes...rinse and shamwow!
I did it in middle school. Doesn't work too well. I even used food coloring putting it on with an eyebrow brush.. That did kind of work. Try Manic Panic. It washes out pretty quick.