Hi @Tezz19,
A warm welcome to the Bunnings Workshop community and thank you for your question.
Unfortunately, this is not something I can help you with as there are a number of variables that come into designing footings for structures of this size.
A good place to start is by speaking with your local council to see what you are required to do in terms of building approval and construction plans. Your council may be able to point you in the right direction in terms of who to speak to.
You'll likely have to speak with an engineer who may require a soil survey in order to design a suitable footing for your veranda.
Let me know if you have any other questions.
Jacob
