Have a look for the council Development Control Plan. It should give you some overview of what is allowed.

In our council area I would not be able to put a carport in front of building line at all. I built a garage with attached carport a couple of years ago and they were very specific about making sure it wasn’t forward of the existing building line.

The DA process involved submitting a plan and engineering diagram. Various site checks to verify everything and check stormwater plumbing etc. They contacted neighbours in case of objections etc.

If under a certain cost threshold you can also go the Complying Development route. Looking at the guide you are probably going to be snookered on the building setback.

https://www.planning.nsw.gov.au/complyingdevelopment#inPageNav-3