Measure and cut the liner to fit the size of the can. The liner itself makes it so easy. You won't need a ruler or anything else.
Cut, peel and attach it around the can. Here is the finish look. I use mine to hold my makeup brushes.
Play around with different liners and sizes of cans for different purposes. I use Pringles cans to store spaghetti and nuts in the kitchen. They also look nice.