Before installing fence posts I am assuming that you already informed you self about the legalities affecting your fence building project and the location of your property line where you will be installing fence posts. You have marked out the location of each hole to be drilled with spray paint or wooden markers. If you are not sharing the fence with your neighbor you should not be drilling the post holes on the property line but move in two to three inches on your side of the property. It is better to be safe than have a neighbor uproot your posts because of boundary dispute. If you need to adjust your markings do it now.
The day of your dig you will need the following equipment and fence materials.
You will need the have the number of fence posts according to your markings and the right amount of premixed concrete for installing fence posts and some gravel.The general recommendation for installing fence posts for most types of fences, is for the fence post to be set in concrete.
You will need a wheelbarrow, long water hose, shovel, a heavy metal bar, a two-way post level, some sort of power operated fence post drill,(you can rent this equipment) a manual post hole digger and the willing friend.
How deep you will need to dig depends on the area where you live.
If you live in an area where frost heave occurs you may want to check on the recommended depth of the hole by your local expert.Usually one third of your post should be under ground.
You will be drilling a hole where your markers are.
If you rented a power fence post drill you will need at least two people to operate it. This is where the help of a friend comes in. If no friend is available you can use a manual digger.
Your other option is to hire out the work to a contractor whose job is installing fence posts. These contractors can also set your fence posts for you. You can work out a package deal and probably get some sort of warranty.