If this is the one you are talking about then you can use it in a number of ways.
http://www.telescopes.com/products/m...inch-6388.html
1. You can screw the collar and silver bit off the end and screw the silver/collar bit straight into the T adapter for your type of camera and put that into the telescope or barlow
2. You can screw the whole lot into the T adapter of the camera and insert that into the telescope or barlow
3. You can pop a 20 or 15 mm eyepiece down inside (after removing the silver bit and collar) and screw the open end into your T adapter and the other end onto the T thread of a refractor or sct (if you have the correct adapter for that end) Using the eyepiece will give you mucho mucho magnification.
The following two images were taken with a 1000mm refractor. First one is prime focus (as in point 1. above) and the second is positive projection as in 3.
Both were taken with film so if you are using a DSLR then you will get slightly more magnification