Give your friend your flight information so they can track the plane online and see if it’s ahead of schedule, delayed etc.

They should look to arrive 30ish minutes after you have landed, though longer than that if there are lots of international flights scheduled to arrive at similar times.

It’s better for them to be early so to ease your nerves of waiting for them and I’m sure they won’t mind as they must be looking forward to your visit.

Also, as a heads up you have to take your shoes off for the security checks.

As for your phone try get an international plan with your Australian provider so you can have texts, minutes and data when you land. Getting an American sim is probably cheaper though if your visit is a longer one.