Start by holding the stringer with thumbs and forefingers, place the spot you want to bend in the tip of a tea light candle flame. Apply a light pressure until you feel the glass soften. Lift the stringer out of the flame to cool and set the angle. Keep the stringer relatively flat as you move on to the next bend. Carbon will burn off in the kiln, so there’s no need to clean.
Just a reminder to always wear eye protection as stringers are pretty delicate and can easily snap. Also, don't forget to allow the bent area to cool before touching. Talking from personal experience, sometimes it looks cool, but it's not!