How to set out the column position of octagonal pavilion

Set the center first, and then set the position of the four pillars (equivalent to the four-corner pavilion). Suppose the distance from the center point to these columns is 2 meters. Then draw a line to connect two adjacent columns, draw a vertical line from the center point, and then the distance from the center point to 2 meters on this line is the position of the fifth column. The following are in order.