Best way to prepare Renaissance Henna

Evening everyone, so I've decided to renew the 2 steps henna + indigo to finally get to my desired shade this weekend.My henna just arrived today and i need advice on how to prepare it for best results..i know there's instructions in the back of the pack but i want people's tips and tricks to achieve best results (deep/blue black in my case).Thank you:)

Bumping my own post just to say that I've prepared my henna the simplest way and it turned out great so i am very happy :D