0:07 Finding 45 degrees using a compass having marked the right angle or assuring it is a true 90 degree angle.
0:30 Using a compass, draw a curve while your point is at the 90 degree angle mark, intersecting both sides.
0:40 Keeping the compass at the same length and move the point to the two intersecting points, drawing a curve which should pass through the original 90 degree angle and create and further cross
0:55 Draw a line between the furthest cross and the original 90 degree.