Each graphic has the decoding on it. Start with the RED CHILDREN RED RED graphic. Look at the top of the page and go downward in the progression (z, b, c, y, x, t, ch, x, ^, g, y, [… + 1]).
There were 3 cypher keys embedded in this string (ch) (^, g) and another dual cypher key & character in [… + 1]. 2x is a silent fourth cypher key in the 38 to 76 "doubling" which applied to the last character. Q kept changing the patterns on add/sub and also the method of add sub. But all stayed within a.b.c.d 1.2.3.4 coding. Q's encoding was the most complex on this one as the "patterns" were changing. You had to recognize the pattern changes (similar to exclusive-OR, exclusive-NOR, Inverter Gate, OR Gate, and AND/NAND gate logic tables - it's easier if you have a familiarity with these devices).