Can anyone help me out. I have a denon 2805 AVR, am trying to get sound to my outdoor speakers, either in conjunction with or separately to my home theatre speakers

It depends on how you want it to work. I grabbed the 2805's manual from Denon's US site, so my page numbers may or may not match the manual provided in New Zealand (it ought to be the same, but who knows...), but I found three options for you.

If you intend for the outdoor speakers to get the same signal as the home theater, then you can simply run speaker cable from the "B" left and right binding posts. This may not be the best choice in some cases, since for movies and TV the dialog normally is steered to the center almost exclusively.

If you want to operate the outdoor speakers as a separate zone (independent input selection and volume control) and your home theater setup is only 5.1 (no surround back speakers, then you can set the 2805 up to use the surround back amplifier channels to drive the second zone (see page 43 of the 2805's manual for instructions on how to do this).

If you have a full 7.1 setup in the home theater and want to have the second zone operate independently, then you need to use the second zone pre-amp outputs to feed an amp specifically for the second zone. That second zone amp can be an old receiver, a used stereo amp, or even a pair of monoblock amps. You can see where to connect it on page 11 of the 2805's manual.