I need help :(

Hello!

I got a Zoo Med 18x18x24 tank for Christmas, and I have no idea how to do any of the really awesome things I see around the site. If someone could send me a link explaining how to do any of the following, or give me any tips themselves, that would be awesome

One of the things that I want to is made a waterfall leading to a pond area, but I really don't want to buy one since the cheapest one that I have found is $40. I was hoping to do a custom one by stacking rocks up and running a plastic tube up the back. I have only seen that in a picture, but I have no idea how to even get started. In addition to not knowing how to build the waterfall itself, I also don't know how to make a pond leading down to it. The waterfall I can live without, but I would really like to have a permanent pond in there for them. I know that I would have to change the water eventually, but i was hoping to put a filter in there so that I wouldn't have to do it too often.

I think that one question alone is a lot to explain, so I will just leave it at that for now