Lay out the vinyl fence where you want to install it. Mark the locations where fence posts are required with a small bit of masking tape or a wooden stake. With an assistant, pull a chalk line along the fence. To do this, each person should hold the end of the chalk line at the ends of the fence, and one person should pluck the chalk line. Follow this line when you are installing the vinyl fence.
Dig the holes for the vinyl fence posts with a pair of post hole diggers. Each hole should be 6 inches deep and 12 inches in diameter. Pour approximately 1 inch of gravel into the bottom of the hole and tamp it down firmly with a piece of 2-inch by 4-inch lumber.
Insert the first fence post in the hole. Slide the rails of the vinyl fence panel into the predrilled holes of the first post. Position the next fence post in the corresponding hole and slip the rails into their holes. Place a pair of bricks under the bottom rail of the fence to help support it until you have poured your concrete. Your first panel of vinyl fence has been partially installed. Continue working in this manner until all the fence panels and posts have been installed.
Mix concrete in a 5-gallon bucket according to the manufacturer's directions. The concrete should be rather stiff, so it will help hold the vinyl fence posts in place while it hardens. Starting at the first fence post, scoop concrete into the hole, using a shovel, until the hole is filled. Tap the top of the concrete gently with the back of the shovel and rake it smooth. Allow the concrete to cure in the holes for 24 hours or until it is completely hardened.