How to exhale scream?

I just want to know the most basic explanation on how to exhale scream. I can inhale but all the tutorials i watch and explanations just dont really explain it at all. i just want to learn how to and preferably something like Austin Carlile screams, because some screamers are good on albums but live they just yell, Austin is an amazing screamer live and sounds like in his album, i dont want to just yell i want to scream. Please help?