Take a cinnamon stick and break it up, boil it in 200mL water for 5 minutes and add different amounts to a few bottles of your next batch. Maybe throw some of the cinnamon in a bottle as well. Goes nice in a Belgian pale ale.
Medieval Brewer here - have done about a dozen Cinnamon Beers. It's a common ingredient in my Gruit Ales.
What I can recommend is using Cassia Bark rather than Cinnamon Sticks.
Why - most commercial dried cinnamon powder is cassia rather than cinnamon.
Cassia will give you a more delicate cinnamon flavour, less burn. Think 'hot cinnamon donut' aroma. Also adds a great woody flavour to the beer as well...
Don't use powdered cinnamon in your beers - you'll never get it to clear.