Sink the head of the round shovel into the dirt in the area you are digging the post hole.
Use the shovel to create the outline of the hole, usually three or four inches in diameter larger than the actual size of the post, so that you have room to pack the dirt in tight around the post after it has been set. Work your way down into the hole with the shovel, putting the dirt to the side to save for later. When the angle is such that you can no longer remove the dirt with the shovel, switch to the post hole digger.
Push the handles of the post hole digger together so that the spades on the opposite end of the tool are spread apart.
Plunge the spades into the hole as deep as you can, driving them into the dirt. Apply pressure on the handles, moving them away from each other. This causes the spades to contract, trapping the dirt in between them. Remove the post hole digger from the hole and place the dirt onto your ongoing pile. Repeat this process until you have gone as deep as you need for your given post.
Pry any large rocks loose with the metal pry bar.
Use the pry bar to break apart large rocks by simply plunging it into the hole multiple times on top of the offending rock.
Set the post in the hole.
After you have set the post, use the pry bar to pack the dirt around the post by filling the hole partially with the old dirt and crumbled rocks and dropping the pry bar onto the surrounding dirt as you fill the hole, packing it in tightly to hold the post in place.