(As Tetrine)

• Pick up Telegram.

Tetrine hates reminders that she can see Nell marks, but doesn't want Rosemary to see her fiddling with the Nell ward on the wall. So you have to distract Rosemary.

• Look at the sewing machine.

(Optional) Looking at Rosemary several times will cause a new dialogue to open up. Try this with other characters, too.

• Ask Rosemary about a pattern diagram. Once Rosemary starts drawing, you can remove the Nell mark by touching it.

• Read the telegram.
• Go to bed.

Dialogue options here impact Tetrine's view on the ending, but don't cause branching.

(As Kalevel)

Your options here have the biggest impact on the ending of Winter's Trumpet, whether or not you offer Devne immortality. Offering him immortality leads to the ending that ties in with Asher's beginning.

(As Markaius) 

(As an aside I made the art for the hall in Tetrine's apartment before I had some unexpected but useful firsthand experience of lath and plaster wall construction. However, I got this detail, and a lot of other old house details, "right" in the Last of the Lords of Ice.)

• Take the package.
• Give Rosemary the package.
• Use the Gaze on Rosemary.
• To get the ending that ties into Asher, take the package again (it's next to the door on the floor)
• Use the Nell (in your inventory)
• Hover the mouse over the bottom of the screen until it says 'travel'. 
• Use the Signet ring (in your inventory) on Tetrine

Look around, then interact with the river.

Pick words/names that fit what Tetrine is experiencing. (Remember Rosemary said 'drowsy'? How Tetrine felt when she fainted?)

• Pick words such as delirium, disoriented, dazed, tremors, indifferent, drowsy, etc....

(As Tetrine)

•  Interact with the door.

• Click on the blood on the ground

From there you see the ramifications of the major choices and can choose how Tetrine perceives the events in the final moment.