Then pour the dry concrete into the hole, I use the handle end of a sledge hammer to tamp down the dry concrete and hold the post in place. Make sure the posts are next to the string where they should be, remember to check that the post are plumb in the other direction. I fill the hole with concrete up to about 6" from the top, once the concrete is tamped and the posts are where you want them fill the rest of the hole with water, the dry concrete will absorb this over a short period of time. I would let the posts set up for a few days as you will be putting torque on them when you stretch the fence. Attach the fence at one end and use either come alongs or some friends to stretch the fence attaching it to eac h post as you go. I should have included this part earlier, but you mentioned gates, you will have to figure out the spacing for the gate opening by what size gates you are using and the hinges that will be used.
