.. Getting a fingerprint

You would need to open it's mouth, gently.

Great. Finally you can touch all the stuff that is on the table.

You are in luck. The wooden box on the basement table is actually an ancient fingerprint kit.

You put the object ( Like, and this is just an example, the mojito glass. ) , presumably containing the fingerprint, on the stand. Open your inventory and place it there.

You take the brush. Put some powder into it.

Then brush the object. Hold down the mouse button and go through the object until you find a fingerprint.

Take a piece of the tape and use it on the fingerprint. You now have the fingerprint stored in your inventory.

Anything, really. Try all kinds of items. Some of them might give you achievements.