Please help me to understand this:

Row 21: With new color, [ch 1, sc in next ch-1 space] 42 (43, 44, 45, 46, 47) times, ch 1, (sc, ch 1, sc) in next ch-1 space (corner made), place marker in last ch-1 made, [ch 1, sc in next ch-1 space] 5 (6, 7, 8, 9, 10) times, ch 1, (sc, ch 1, sc) in next ch-1 space (corner made), place marker in last ch-1 made, [ch 1, sc in next ch-1 space] 42 (43, 44, 45, 46, 47) times, end with ch 1, sc in last sc, turn; change to next color in Color Sequence—94 (97, 100, 103, 106, 109) sc.

This is from Doris Chan project. Before this row it says:

Shoulders
Note: Shoulders are now "grown" by making two corner increases equally spaced from center of back neck. Mark the ch-1 space at center of each corner, move markers up as work progresses.

I am challenged in this area but eager to learn.
Appreciate your help to understand it.

Thank you for your help.