Creating a waterfall in your backyard is no big deal, and just requires a little imagination, some materials, and effort.
Start with finding the right place for your backyard waterfalls, somewhere secluded in your garden where you can also have some shade. You will require a pond of a decent size that still leaves you with space for your garden. Once you have found the spot, mark out its shape as you have conceived it, and dig up the earth to form the pond.
Find some stone of any shape and build a wall on one side of the pond. The earth from the pond can be dumped behind this wall. Now line your pond with underlay and a liner of a size that covers the whole pond and more. Put in some piping at the lowest point in the pond and lead it to a suitable pump. The pump should lift the water from the pond to point at the top of your stone wall and allow it to fall over it.
There you have your waterfall.