Draining & replacing coolant / engine block drain location?

Hi all. I recently got a new radiator, but want to first drain the engine block & push some air through too (to really empty it out) before I fill up with Evans waterless coolant. Where can I find the engine block drain?

Secondarily, anyone have experience with Evans? I'm sold on it, but don't know if I want to first use their prep fluid and then drain before I finally fill with the coolant. Any info is appreciated! Thank you!!!