First, center the octagon so that the top and bottom sides are parallel. Then label the point to the left of the top side as A, and continuing labelling the points to H.
Since we have a regular octagon, the interior angles will all be 135o. which is a property of a regular octagon. The angle from the perpendicular will be 45o.
We will use compass points to define the directions.
So, start at A and proceed due East to point B
At B, turn 45o South-south east to point C
At C, proceed due South to point D
At D, turn 45o South-south west to point E
At E, proceed due West to point F
At F, turn 45o North-north west to point G
At G, proceed due North to point H
At H, turn 45o North-north east to point A