double checking if this oil goes in transmission and rear diff

Hey guys, so I asked about the demand drive fluid, and turns out it goes into the front diff. Thanks for that!!

However, I am not sure about the rear diff and transmission. Does the transmission and rear diff drain on the same plug? or do you need to drain oil from transmission, close it back up, then rear diff?

https://www.amazon.com/dp/B003AYY27U…I1SF9FI522RDFM

it is the 2015 polaris sports man 2 up 570 motor. And would I need 1 or 2 bottles.