With the Morrowind Expansion for The Elder Scrolls Online there are two ways to get to Morrowind, or what it will be referred to as the island of Vvardenfell. You can start a new character that will begin at level one for the expansion, which is the only way to try out the new Warden class.
If you choose the new character option you’ll be given all of the same options that you are given when starting a new character including the new tutorial for the game. Regardless, if you do choose the new character option the game will automatically start you in the Morrowind Expansion’s new location of Seyda Neen in Vvardenfell. You DO NOT have to create a new character to play this expansion.
For those that do not want to start a new character for Morrowind, you’ll need to use the fast travel option to get to the Morrowind content. Once you’ve gotten access to the expansion there will be a single Wayshrine located on Vvardenfell that is at Seyda Neen as well. Pressing M on the keyboard will open the map for Elder Scrolls Online, from there just navigate to the Wayshrine and press the appropriate button to fast travel.
For those that did not pre-order the game Morrowind will be accessible on 6/6/17.