Verified answer

There is no level requirement. All you need to do is being called by the Greybeards after you killed your first dragon, and you will find cultists searching for you in a random city you enter. After you killed them, just loot one of them and you will find a note. The rest will be obvious.

Also make sure the dlc is active and running in your game.

What Is Dragonborn Dlc

You can start it at any level, but it's recommended to be level 10 (that's when the rumors arise about it).

You can go to the area by going to Windhelm Port, there is a small ship (more like a boat) with a number of Nords on it, talk to him and he will ask if you want to go to Solstheim. (I probably spelt that wrong)

It costs a little bit of gold, but once you've been you can fast travel between Skyrim and there by the arrow at the top right (Skyrim) or bottom left (Solstheim) of the map.

Edit: Oh wait, there's a quest line off the isle that's added by Dragonborn? I actually didn't know that.

I just barely got the DLC but, you can start any time as long as you completed the quest (fully) "dragon rising"

but what I did was buy the courage spell from farengar (or anybody else who has it) and cast on the jarl of whiterun until your illusion skill reaches you to level 10 (witch is the RECOMMENDED NOT REQUIRED level) or else you will lose against the first enemy

in other words your *** will be handed to you direcly shiped from amazon

purely tried 4 circumstances already to get carry of keeps combating @ fifty 9%. now the 5th time the full call is on the show it became into in basic terms dragonborn now it says the elder scrolls v skyrim dragonborn so optimistically it is going this time. nope comparable element nonetheless don't comprehend what is going on with it. optimistically somebody has an answer day after today or in keeping with possibility it purely works.