This is not a pattern but a fundamental exercise, the first one a 10th Gup beginner works on. It teaches turning, fixing the stance and punching in the four directions of the diagram before tackling the first pattern. The book gives two versions — one starting with the right foot, one with the left — so that both hands and both feet work equally.
The low block deflects a front kick or an attack to the belt line outward.
The middle punch goes to the solar plexus of the opponent you have just blocked.
The left-hand column shows where you face and which stance you form, seen from above; the red foot carries the greater weight. See the direction chart in the Encyclopedia if you cannot remember where each letter falls.
Summarised from Choi Hong Hi, Encyclopedia of Taekwon-Do, volume VIII. The order of movements and the diagram follow the book; the explanatory texts and the footwork schematics are our own work.