Just a quick post to show you the location of this new DLC quest for The Witcher 3. The quest i a lot of fun so I recommend you download and give it a try.
Download the DLC, then fast travel to the village of Fyresdal in Skellige. Pick up the contract from the notice board then speak to the merchant nearby to start.
If you cannot get the DLC to start then try re-downloading it, then reset your console before loading up the game. The first time I downloaded it then it did not work until I restarted my ps4.