Billi
First rule of collimation is don't stress about it! With a scope like that, pretty good collimation is all you need. A good guide to basic collimation is here
http://www.astro-baby.com/collimatio...on%20guide.htm
The thing with a film canister is that it is used to get your eye centred in the focuser. That is all it does. So get a bit of card, cut out a circle the same size as your focuser tube, punch a hole in the middle, hold it over the end of the focuser and look through the hole. It is not perfect but will enable you to get pretty close with your collimation.
Malcolm