What about this artifact could tell us that the people living at that time possessed stone-craving skills

The artifact in question is known as the Great Sphinx of Giza, it was created in about 2500 BCE in Egypt.

The fact that the statue is of an animal figure.

This is because the statute has an animal figurine. Limestone was a difficult stone to carve,and the fact that the artist was carved into such an animal like figurine, suggests stone carving techniques.