Today will look like a lot of work but it will go quickly.
Sew the 1-3/8″ x 5-1/2″ colored strips to both long sides of the background 1-1/4″ x 5-1/2″ rectangle. Each block will need four of these units.
Sew two of the above units to opposite sides of the center star, matching the color in the center with the colored strips.
Do this will all 18 of your center stars.