How do I get down the stairs?

Hint 1 of 8:

You'll have to fix them.

Hint 2 of 8:

Or at least find a way to cross the gap.

Hint 3 of 8:

Look around -- very close to you there is an object you can carry.

Hint 4 of 8:

The wooden box may be too heavy.

Hint 5 of 8:

Just open it.

Hint 6 of 8:

Read the note.

Hint 7 of 8:

What's that, next to the box?

Hint 8 of 8:

A piece of wood.