Dig a hole 2 feet wide, 2 feet long and 2 1/2 feet deep.
Mix the concrete according to the instructions on the bags of concrete and fill the hole with wet concrete.
Insert the beam into the hole at least 2 feet into the hole and use the level to verify that the pole is traveling straight up from the ground.
Allow the pole to sit for two days for the concrete to dry.
Position the backboard against the pole so that the top of the rim is 10 feet above the ground and then mark on the beam the locations of the holes in the backboard assembly for mounting the backboard.
Drill a hole through each mark.
Attach the backboard to the pole with bolts and secure in place with nuts.