$1911

Can anyone show (preferably) me what to do on a pattern directions of how to do a straight arrow down knot? I understand the left arrow knot and the right arrow knot. What do I do for a straight down arrow (or a straight up arrow)?

A straight down arrow is only shown in two-colored alpha patterns. It means: make a knot with the base-string (vertical string) in the opposite direction of the other knots in the same row (that are made with the background string).
A straight up arrow doesn't exist as far as I know ...