CUBE IN OBLIQUE PERSPECTIVE
First of all, you have to construct the visual field, as explained in the parallel perspective.
Draw the support, horizon and distance lines and do not forget that you have to consider the measurement of 3 meters between the view point and the distance line.
Work to a scale.
Construct a square with a single vertex leaning on the support line.
Find the perspective center of the square.
Do not construct a square in the vertical position. Incline it slightly to the left or to the right.
Starting from the perspective center in a vertical line, find the view point 17cm away from the support line in the downwards direction. Mark the view point there.
From the view point, sketch lines parallel to those of the square up to the distance line and perpendicularly to the horizon line. Mark the vanishing point 1, the depth point and the vanishing point 2.
See in pages 70 and 71 (figures 38-B, 38-C, 38-D and 38-E) the several phases of the cube construction.