Measure a flat, level area of the yard close to the house to place the carport. The carport will measure 20 feet by 10 feet, so make sure to clear an area slightly larger than that. Mark the outline of the carport by marking four post holes, one on each corner, and two post holes, one in the middle of each long side.
Cut two posts to a length of 9 feet. Cut the next two posts to 9.2 feet. The last two posts should be 9.5 feet. This graduated height will help the water run off of the carport.
Dig the post holes 2 feet deep. Mix up the concrete and fill the holes with it. Fit the post brackets into the holes. Make sure the brackets all align the same way so you can screw the roof into place correctly. Allow the concrete to dry for 24 hours. Fit the posts into the brackets and pour concrete around the base to set them in place.
Cut the beams to fit between the corner posts and the middle posts, along the outside of the posts. Bolt the posts to the beams using galvanized angle brackets for stability. The beams should cover the tops of the posts like a skirt. Fit a longer beam between the two front posts and attach in the same way. Make sure the top of the beam aligns with the top of each post.
Cut one long beam to fit across the middle length of the carport. Bolt into place with angle brackets. If necessary, use two smaller pieces and use brackets to hold the pieces together in the middle.
Cut six beams to fit between the long middle beam and the outside beams for each side of the carport. Bolt the beams in place.
Nail a metal or PVC roof to the top of the carport. Place the nails every 16 inches along the edge of the roof into the beams.