How to make hair curly?
They have curling irons for that. A straightener would be extremely difficult to curl your hair. If you don't have a curling iron, you can use the curling-pins and leave them in your hair overnight and uncurl them in the morning. Or, you could use the straightener and make flips in your hair. But use the straightener as a last resort, since it's hard.
Get a perm or you could use a curling iron.