How to access Whispers of Oblivion

So it took me way too long to figure out how to "unlock" whispers of oblivion after pre-purchasing LotV and I figure I'd share the knowledge.

On the battle.net launcher you have to switch the region/account to Beta: LotV.  It should then download and update it to the proper version.

I spent way too long trying to see if it was in master archive or somewhere else.  Thanks to Kelthar for posting the seeminly simple solution.