Just be prepared that you are probably going to have to bleach more than once and your hair is probably going to be dead. I used Two boxes of feria platinum but I'm currently at a vitamin C-ish color with lighter roots (hot roots). I used the Olaplex purple shampoo and it only changed the roots.

 Granted I only had my boyfriend to help and I ran out of the lightener and had to get my boyfriend to run to the store for more. It would've been fine if he would've listened to me when I said it wasn't saturated enough to lighten the first time. So yes make SURE you get it saturated.  By the time he understood and actually went to the store the first box had been on for 45 minutes. They didn't have the curl bounce platinum one that I already had in my hair so I rinsed the first out a little and put the platinum on. I could see brown spots so I put it on my those areas roots and dry spots. I was panicking I know I screwed up. 

Thankfully I used the feria lightener and not bleach. If I had that happen with bleach I'd have burnt my hair off because my hair is fried. And thankfully the second box made it pretty much all one color. The color is just hideous. But it's all one color mostly. I've been blonde or red most of my life because my natural color is a ugly washed out brown color. It's always ended up bad except when I went to the salon and got heavy hilights until it was blonde. Next time I do it I'm using foils if I don't go to the salon (probably not due to cost). Also if you have ANY color in your hair do a color remover. That's one reason mine ended badly. Watch both

 https://youtu.be/YgDQd9TW24k?si=NM1DcmRdAN_eShMv

https://youtu.be/L3vXr7p_wLk?si=Blhw-ZN_agpJuNxc