Find the pullbars and the secret doors:
Move forward to the first crossing. Turn into the corridor on the left. There is a pullbar. Activate only once!
Go back to the crossing and choose the corridor straight ahead. You pass a small room witth rats in it, go straight ahead. You land in a hall with stalactites. Move to the middle and turn right. Go ahead until you pass a stone pile with a woman’a head on it. Look behind a bit to the right, there’s a stone pillar with a chain on it. Pull the chain. Pass the pillar to the left and find there the secret door that is now open.
Move to the next crossing. Use the corridor left and find at the end the next pullbar on the left wall.
Go all the way back to the first crossing. Use the corridor right. You will encounter a trap with downfalling stones. Move straight forward into the next hall. At the backside is a stone altar with a pullbar.
Turn back to the entrance of the hall, to the left there is now the secret door open. Now just move straight ahead to find the exit to Teia.
Isles of Teia:
Move between the isles by boat, through the portals (no small isles reachable through portals) or use the boots of waterwalking you can find inside the tavern at Bre (Land’s End), these are also craftable (for your followers).
Activate the boats with a button or ship’s wheel. Navigate the boats with the arrow keys or WSAD keys. Important: Before you stop sailing, make sure your boat is not moving anymore. Otherwise you maybe will not find the activator anymore.
Bre (Land’s End):
There are two civets, harvestable trees, a garden with harvestable flora, chicken and eggs. There is a tavern with actually no owner. Find potions, a bow, boots of waterwalking. Bre lies at the southborder of the isles world. The backside is open and you can sit there and watch over endless water. Outside the borders the water is very shallow and there are no underwater plants and no navmesh.
One of the portals lead back to Skyrim.
Isles of Rhun or Southisland:
Don’t just rush just through. Harvestable flora is between shrubs and other plants. Most trees give firewood. Earn peaches and bananas. You can dig up some sandpiles. Amphoras contain loot (not if player is too low levelled). Find the hidden entrance to the Ayleid dungeon: there are steps behind shrubs in the upper part of the isle.
Look around and find some destroyable urns. They contain potions you may need later. Find your way down under until you come to the Halls of Memories. Touch the spheres and learn about the dead children of the Ayleids. They refer to a quest that’s not implemented, it will be a part of Tasheni Followers.
Turn five times through the left door and then through the right to find your way through. You will encounter enemies.
Many Ayleid and Daedra enemies. Destroy the Great Welkynd Stone. Collect shards you can sell later. Find the key atthe body of Queen Morrigana. Find the door behind the throne.
Some enemies. Find the chest and get your reward. Go back into the Great Hall. At one wall there are four doors, three not usable, but the one most left leads the short way out of the dungeon. You need the key from the Queen.
Molavar or Volcano Isle:
Not much to do. Encounter a dragon. Eyecandy.
Just eyecandy. Hunt some animals. Climb up to the highest point. Enjoy the storm.
Ilmen (Main Isle):
Faster longboat at the eastside. Entrance to the Crystal Cave. Lots of critter, eggs and fish. There’s a seat upon the high rock.
Collect glowflowers. Find a dead stag. Make your way to the great hall.
Encounter three water hags. The willow-the-wisps will turn hostile if you got too near. Their fire is deadly. The sprites flee from you. They contain ingredients.
There is a ramp right of the entrance that leads up. Cocoon houses are empty right now. Make your way over the high ramps until you find the exit.
At several places you can dive and find chests inside ruins and encounter hostile seaanimals. Seacows, seals, sharks, tigerfish, orcas and whales are patrolling wide distances, so you will encounter them always at different places. Some seacows and octopus are local. Octopus will chase you, if you get too near.
Some small Isles:
Collect new ingredients. Find some doomstones.
If you encounter any issues, please post it in the comment box.