with each other. for my 1' planter i needed 6 in addition the two bottom long braces. i layed them out as i cut them and measure them against the short side pieces to make sure i had enough for the base. next i used put all the planks together and measured and cut 3 short pieces to make a screw the base into keeping it off the ground.
as i don't have a truck i put all the piece back into my car and assembled it at my house.
i used self-starting / self tapping screws. if you are going to use regular screws you will need to drill pilot holes 