You're off and running now Ezy.
Better focus than I got on my first DSI shot.
If you have registax then you can stack individual images as well as video. But the DSI software will automatically stack images for you as you capture. Basically you have two choices with the software, stack as you go or save each image.
The way I understand it with stack as you go you set a minimum quality that has to be met and the program will automatically select those images that meet your quality settings and add it to previously selected images from the capture session.
If however you select save each image, once you've completed a session you import them into Registax en masse and treat them like an avie.