Here's a lot of good reading for you. http://motorbicycling.com/showthread.php?t=11815
The Google Custom Search feature can provide you with a lot of information. Questions that have been asked and answered hundreds of times can be found with a simple keyword, such as 'tensioner'.
Good luck. The chain tensioner issue is one of the most common problems encountered by the first time builder. You'll figure it out.
Have fun, ride safe.