What is the recommended method for installing a concrete footing for a 6x6 post?

The recommended method for installing a concrete footing for a 6x6 post is to dig a hole that is at least 12 inches in diameter and 24 inches deep. Place a cardboard tube form in the hole and fill it with concrete, making sure it is level. Insert a post anchor into the wet concrete and allow it to cure for at least 24 hours before attaching the post.