Lay two cedar posts parallel, and 36 inches apart. Screw a 4-foot board to the two post so it lays perpendicular to the board, 6 inches from the left end, and so there are 6 inches of overhang at both ends of the 4-foot board. Repeat this process with your last two posts, and another 4-foot board.
Cut a 1-inch-wide notch that is 4 inches deep, perpendicular to the long edge, and 8 inches from the end on one of your 8-foot boards. Use the hand saw to perform the cut, and the chisel to knock the piece of wood out. Cut another notch with the same measurements 3-inches from the first, towards the center of the board, on the same side. Repeat this process on the opposite end of the board so the cuts are symmetrical. Repeat on every 8-foot board.
Stand the posts upright so they are parallel, 6 1/2 feet apart, and so the 4-foot boards are between the posts. Fit the two inside notches on the 8-foot boards over the 4-foot boards. The 8-foot boards should be perpendicular to the 4-foot boards. Use all four 8-foot boards; place one on each side of every post.
Fit the last two 4-foot boards into the notches on the outside of the post. All of the 4-foot boards should line up. Screw all the boards that touch the post, to the post. Use three screws on each board.
Notch each 5-foot board with four 1-inch notches, each 2-inches deep. Space the inside two notches 17 inches from the center of the board, and the other two notches 42 inches from the center of the board. Place the notches of each 5-foot board over the 8-foot boards. Space them evenly.
Use your angle finder and circular saw to cut the ends of the 3-foot boards at 45-degree angles. The board's longest edge should still equal 3 feet, and should look like a trapezoid when laying flat. These are the support boards for your pergola.
Screw one of the 3-foot boards to the 8-foot boards, and the other end to the post. The edges that were cut should be flush with the edges of the post and the 8-foot board. Repeat this process in each corner to complete the pergola.