Welcome to the Bunnings Workshop community @NewbieHP. It's fantastic that you've joined us, and many thanks for your question about low-level decks.
You might like to start by telling us how high above the soil the decking will be. We can then provide information about how you'll need to prepare the ground and whether there is enough room to create a deck. Choosing what decking to use is one aspect, but you'll also need to decide what you are building the deck's structure from as these timbers will be even closer to the soil.
I suspect you'll need to lay a weed matting or geo fabric with crushed stone on top of it. You might also need to run additional drainage under the deck to allow water to escape. Geo fabric and weed matting will serve a similar purpose, but the geo fabric is designed for drainage situations, so that would be my recommendation.