Cassie, to hook up your Canon DSLR to the scope you will need some way to adapt the Canon bayonet mount to the scope. When you say a T-Ring I assume you mean something like this:
http://www.bintel.com.au/Astrophotog...oductview.aspx
which will allow your camera to slip into the focuser tube. However to attach it to your Canon you need this as well:
http://www.bintel.com.au/Astrophotog...oductview.aspx
together these are all you need.
For bright objects like the Moon you can use the Auto setting on the camera. However, for faint objects you will need to shot long exposures to gain enough light to make out the object, and that means using the Manual or Bulb setting on the camera to control the length of the exposure. A cable release or intervameter is also useful for making sure you don't bump the camera during the start or finish of the exposure which can blur the image.
Good luck.