Using this baby sweater suit is easy - just put the sweater on your baby's upper body and then the pants on their lower body. When choosing a size, remember Asian sizes are smaller, so pick a larger size if in doubt. Check the size chart carefully before buying. For maintenance, it's best to follow the washing instructions on the label. Usually, you can machine - wash it in cold water on a gentle cycle. As different computers show colors differently, don't be surprised if the actual color is a bit different from the picture. If you have any questions about sizing or anything else, feel free to contact our customer service.