If you are from Italy you can watch it at VVVID.
For English Subs:
http://www.dramanice.us/prison-school/watch-prison-school-episode-1-online
So far we have 2 episodes. It is pretty decent.
I'd rate it 7½ / 10
Live actions are bad the more of times, but this after the Death Note 2015 Live Action is pretty cool and solid and doesn't suck. So watch it!