Your plants will either be large "plug plants" or "bare root". They will arrive in plastic bags, and, if you have ordered a collection, a brief description and instructions as to where to plant them. They will either need to be planted in boggy areas, at the water level, or submerged.
If you have a plastic pond or butyl liner you'll need to use a container to plant into - have a look at our preplanted coir products if they might be helpful. We don't sell aquatic plastic baskets but you could use them, or something similar adapted from garden pots. We also recommend making sausages or pots out of hessian, which has the advantage of rotting down. Fill with subsoil or low fertility growing medium - specialist aquatic soils aren't necessary.
Planting aquatic plants could not be easier; just push them into the mud! Water lilies can be slightly more difficult as they're planted in deep water. Tie twine around the tuber and a stone, then chuck the assemblage in where you want the plant to grow. If your order includes oxygenators they will come crimped together in bunches. This will weigh one end down, allowing them to establish. Just throw them in.