“Black Book: The Winds of Change” is the Side quest in Skyrim - Dragonborn
Start by going to the Southeast. Go through to the book archway and then go up the stairs beyond.
On the landing, look to the right to watch for a Seeker. Next, go to the Northern portion to find a scrye. Interact with it to open the gate forward.
Go through the gate and over to the far wall. Turn to the right and interact with the Scrye to open the door between to the walls.
Go to the right and go through the door that just opened after that.
On the other side you have another Seeker to deal with. Deal with it and then head to the South through the swirling pages. On the right, just before the door, you will find a scrye. Interact with it to open the door to the South of you.
Go on through the door to find a large open courtyard. Continue directly to the South in front of you. Go up the ramp and to the landing at the top of it. There, you can find another scrye to interact with.
The first touch will trigger an enemy, from the large fluid pool, a Lurker will appear.
Head back to the scrye after you defeat the lurker. This will open the gate to your West.
Drop back down to the lower part of the courtyard you are in. Go to the Northwestern corner where you will find another Scrye.
Activate it to reveal the stairwell you need to go up to the newly opened gate.
Go on up the stairs. You will find Black Book itself again. This tome will offer 3 powers. You will be able to choose any 1 of them.
From now on, reading this book will bring you immediately to the podium. There, you will be able to freely change your power.