crochet hat brim/waistband for beginners. instruction in the description below. 

For this, after gathering all the material, start by making a chain at your desired length. For hat, I usually make between 8 to 13 chains. And as for waistband, it depends on how wide you want it.
For row 1, make 1sc in the 2nd ch from the hook and in each ch till the end. Ch1 and turn.
Rwo2: 1 sc in the 2nd ch from the hook and sc in each st ( in the back loop only) around.
Repeat row 2 until desire length.