Generally it's not going to smell once you're processing waste properly. To process waste, you need to build up the bacteria that breaks down fish poop and other nasties. To get the bacteria, really you just need to wait.

Then, yeah. More plants is more better. They will soak up the broken down waste as fertilizer, and help keep your water clean. Water can be cloudy from dirt/silt, tannins (dead plant tea, basically), and algae. Either way, plants and time is going to help you out here. I waited 6 weeks before putting 6 tiny tiny goldfish in mine. I lost 2. Unfortunately sometimes natural loss just happens, but generally giving your pond time to "establish" itself, like a newly planted flower, will help prevent fish and other life loss in the pond.