The pattern includes general written instructions, plus charts of the Fair Isle motifs.

There is a background colour and 4 other colours used for the Fair Isle motifs. You never use more than 2 colours in any given row in the entire blanket.
Yarn requirements according to the original pattern:
Main colour: 1250 yds/1143m
1st colour: 250 yds/229m
2nd colour: 250 yds/229m
3rd colour: 250 yds/229m
4th colour: 250 yds/229m

Required techniques:
Casting on, casting off, knit, purl, increases and decreasing, Fair Isle (stranded) colour work: The blanket is knitted entirely in stocking stitch (stockinette) except for 3 rows where simple increases and decreases are used.
Sewing: The blanket is knitted in one piece, folded over at the top (a picot edge) and then the 3 sides are sewn up.

The instructions for the back of the blanket is very vague. Clarification: When you begin the back section (which is just a continuation of the front after making the picot edging), continue on in the smaller needle size in stocking stitch over the 149 stitches until, when folded at the picot edge, the long sides of the front and back will be the exact same length. Many people use the 5 colours in stripes for the back.

The accompanying article to the original pattern states that it originated in Shetland. However, further research indicates that its true origins are in Fair Isle (as jumpers/pullovers knitting by grandmothers when their grandsons were born, made in adult sizes and begun wearing when the boys were teenagers) and in Orkney (as pram blankets).

Errata: In the original pattern printed in the magazine, the instructions for following Chart D are under Chart E, and vise versa.
After completing the charts for the front of the blanket and the decrease row on the right side, the instructions read to now knit 26 rows in stocking st. That should be 27 rows so that you will end with purling a row on the wrong side before beginning the picot edge row on the right side.