Dig the post hole to the necessary depth, using a post hole digger or hole auger. A fence pole requires a hole depth of 3 to 4 feet if it isn't anchored. If you are anchoring with cement or another method, a hole of 18 to 24 inches may suffice.
Affix any necessary anchoring devices to the bottom of the pole. The simplest anchor, the deadman's anchor, requires nailing a 10- to 12-inch piece of board perpendicular to the pole near the bottom edge of the pole. Alternatively, nail four brace pins halfway into the pole near the bottom edge, spacing them equally apart, for use with cement.
Set the pole in the post hole, with the anchor inside the hole if applicable. Set a liquid carpenter's level on top of the post. Adjust the pole until the bubble in the level is between the two level lines marked on the viewer.
Fill the hole with premixed cement if you are using brace pins. Use enough cement to cover the brace pins, then use backfill or gravel. For other anchoring methods, use only the backfill from the post hole or fine gravel. Tamp the fill firmly around the pole base.