The Entrance: Go to Suri Kyla. Go all the way west of town. There will be a boat along the shore just west of it (like in Enedwaith). It's actually nowhere near that relic from the Calm Before the Storm.
Some bugs to watch out for: The entrance will let you in, but it won't let you back out. It's kind of like walking into a glass door.
So if you go in to explore and defeat the big ol' bear, leave using your portrait.
If you need to reset the bear by running out of the gate, the bear will chase you and get stuck and bugged out in the gate. He will start screaming at you to stop running around and stop wriggling, over and over in rapid succession.
The second floor is bugged (after the first boss). It will be fixed in next update. There are three bosses in total. The entrance is in Forochel. - amlug