Color 1 is the color of the body and color 2 is the color of the top. If you want the bootie to a solid color just choose the same color for both option.
 
PLEASE NOTE:the sizes goes by what the child wear not by age since this is crochet clothing. For example the baby is 6 months but wears 0-3 in clothing then you will need to get the size 0-3.