.. Waking up the Tree of Doors

The ravens are disturbing it. Get rid of the ravens.

You did it already once, remember?

Yup. Scare the ravens away. ( First, run towards the ravens on the ground. )

Next, the rest up there.

Use pebbles. You will find them, eventually.

Help Trollhilde, first. ( After that you get access to her lair. Take the pebbles from the ground. )

Use them against the ravens.