Before starting to build a fence it is important to pre-plan the operation, directions on how to build a fence can be found online but there are a few important steps to take into consideration before you even think of digging that first post hole or buying any materials.
You will need to buy or draw up a set of plans and take these to your building inspector to check that you will not be contravening any building codes that apply in your area, if applicable you might also need to get passed the local tenants association, some areas demand that you have a permit. Your set of plans will also enable you to work out the amount of wood and materials needed to complete the project; once you have this information you can work out the cost involved with the help of your local supplier.
While you are in contact with your building inspector (or planning officer) find out how deep the frost line is for your area, you will need to sink your fence posts well below this level so that your fence does not get knocked out of line should there be a severe frost. Make sure that you use a good sealant on the part of the post that will be below ground.
You can now mark out the position of your post holes from your plans, start with the end or corner posts. Dig your holes and set up your end or corner posts using a spirit level to check that they are truly upright and support by nailing a prop or brace to each side, you can now backfill or set into place using cement or concrete.
Now that you have your corner posts in place you can measure out the line of the fence by stretching a string from one post to the other to make a perfect straight line and mark out the position of your intermediary fence posts by driving a stake along this line at the correct spacing as shown on your plans, double check these measurements.
Now dig out the rest of your post holes and set your posts in place using your string line and spirit level to keep a perfectly straight line. Use braces or props to hold your uprights in place and backfill with your material of choice then leave for a day or two to allow it to set.
You can now add your fencing or whatever you have chosen to go between the uprights, if hammering seems like it could dislodge the uprights it is better to use screws, paint on a good sealant and your fence will last for years. With a good set of directions on how to build a post your project will have a professional finish and run smoothly.