When you arrive from Melbourne Airport (also known as Tullamarine Airport), you can catch a taxi from outside your terminal or you can get the Skybus. The Skybus has a service called the Melbourne City Express that stops at Southern Cross Station. From there it's just a short walk or tram ride to the venue.
Here you can buy a ticket for the Skybus:
https://www.skybus.com.au/melbourne-city-express/buy-tickets/
Public Transportation
Probably the quickest way to get around in Melbourne is to use the public transport system.
Tram rides in the Melbourne centre are for free. Outside of this area you will require a MYKI card to pay for your ride. A MYKI card can be bought at the vending machine e.g. at Southern Cross Station, which is located in 10 min walking distance from the venue.
Here you can find more information: https://www.ptv.vic.gov.au/
And here you can download the app where you can plan your journey and top up your MYKI card:
https://www.ptv.vic.gov.au/footer/about-ptv/digital-tools/mobile-apps/