This type of building is used for several thousand years already and is very easy to construct.
Choose a level ground without the risk of flooding. Dig holes in the ground about 50×50 cm wide and about 50-80 cm deep. Holes are needed in the corners of the future shed and as many as you wish may be added along the sides.
Put a layer of gravel on the bottoms of the holes for proper drainage. Cover the poles with waterproof insulation like tar, put them into holes and fill the holes with cement solution to form a cast concrete founding. Poles should be secured in vertical position until cement hardens. Making front row higher than the back row provides you with a simplest roof base.
Nail some bars to the tops of the poles to form a carcass of the roof. It can be flat or have slopes, the choice is yours. Secure corrugated roofing material sheets to the bars with screws or nails. This is the easiest answer about how to build a perfect pole shed yourself. You will make it easily!
Do It Yourself: How to Build a Pole Barn