After you shower apply a small amount of leave in treatment to detangle. I like this RedKen one to protect my locks from heat.
Add a heat protectant oil if you'd like. I use Olaplex No7
Rub them both together.
Apply the leave in treatment and oil on your ends only.
I use the brush attachment with the round ends to get my hair 80-90% dry before I use the curling barrels.
I use the thicker barrels to get the blowout look. The thinner ones will keep the curl defined.
Leave the barrel for 10 seconds in the heat setting.
Then use the cool blast for 10 seconds or until the hair feels cool.
Brush out your hair and you're done!