Hi @bryceyj9,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
I'd suggest you have a quick read through Considerations For Building Outdoor Structures to start with.
You'll want to start by confirming with your local council what they require. In some areas, it may be necessary to have engineering plans drawn up and submitted to the council for approval, so it is important to get the right advice during the planning stages.
With pergolas, it is not just as simple as one timber fitting all scenarios. Two main variables need to be considered to select the correct timber: the type of roofing material, if any, and the wind classification of your area.
Our supplier, Lysaght, has this handy Wind Classification Design Guide, which you can use to determine the wind classification of your area.
You can then find pergola span tables, such as these Woodhouse Span Tables, which will show you what timbers need to be used in what scenario.
If you could advise what wind classification you are in and if you are installing a roofing material, I would be happy to have a look at what material might be suitable.
Jacob
