.. Opening the safe

You need to match correct symbols on the notch at the left.

What is it with some symbols have that green line behind them?

Maybe Santa has some kind of a code breaker in his office. ( The paper from the cuckoo clock.)

Use the paper you got from the cuckoo clock on the safe. You can now match it over the combination disks.

The paper has the notch on the left and that line on top.

You should turn the disks so that the green line points upwards. Then you can match the paper on the disks.

Like this. Notice how the disks are aligned.