Plastic rollers are the best option to create curls over your hair. It will be small circular tubes which will be stay as a base for the hair to get wrapped around. There will also be small holes in these tools that would act as ventilation for your hair to get dried. Those who are looking to create the curls without using any heat styling tools, then the plastic rollers can be the right choice for them.
First shampoo wash your hair and condition it normally. After the conditioning make sure to rinse the hair and maintain it slightly damp. Then apply a small amount of gel throughout your hair as it will help to keep the roller in place. Now you can brush the hair to make it free from knots and then mist the entire hair with detangling hairspray if you have severe knots. Next comb your hair and take one inch part separately. Keep the roller at the hair ends and try to roll it towards the scalp before securing it in place using the hair clip. Use the same method throughout the hair and once you have used plastic curlers all over the head, dry it with a hair dryer for one minute. Make sure to keep the hair dryer far away from your scalp and focus mainly over the curlers only. Let the curlers stay on your hair in the night and gently take it out in the morning to get the curls.