Buy your adult birds - one drake to a few females, get an incubator and hatch eggs. Start your own flock.
Your water system seems fine, I just had a natural filling pond, and the rain kept it fresh enough. The paddling pool will need emptying every day - they are mucky birds. And if it's not too full your drake won't drown the ducks when mating.
As to food, I used layers pellets as mine were the same pets for eggs, but if you get them pre point of lay, you can get specialised growers food from the likes of McCaskey's or other country stores. I used stainless steel dog bowls fro food as they're easy to rinse out and sterilised if necessary. You'd need a few of them as they do knock them over.
Have fun, you'll love their antics. I gave mine away when I moved, and I regret it now although one of my girls was a noisy witch
so maybe my new neighbours have been saved from that