I came across this video tutorial from Pipe Dreams, the makers of the popular EzeeDrone brand of drone reeds. There some great detail here, regardless of the type of drone reeds you use. The video quality is nice and clear.
The basic steps are:
1. seat the reed solidly in your drone
2. adjust the bridle so the reed is taking the right amount of air pressure
3. adjust the tuning screw so the drone produces the right pitch
Watch the video.