Welcome to the Bunnings Workshop community @Bibes09. It's great to have you join us and many thanks for your question.
There are plenty of online tools to design your own deck. I've used your provided sizes to create a basic layout. This uses a traditional system of a 90 x 45mm joist over a 140 x 45mm bearer. You should find this guide useful if you need to build the deck in a limited height: How to build a low-level deck by @Adam_W.
I trust this will give you a starting point. You might like to create your own discussion so we can talk more about your project and questions.