Engineering careers require tertiary level qualifications.
It’s a broad area so checkout university websites to see which engineering degrees appeal to you. If you already know what you want to do, it’s worthwhile specialising in a specific area of engineering, for example completing an Aerospace Engineer degree if you’re passionate about aerospace.
Maintenance careers can start with apprenticeships.
To qualify as a Licenced Aircraft Maintenance Engineer, you need to pass the relevant CASA exams, have four years of aircraft maintenance work experience and you must be 21 years of age. You can start your training with an apprenticeship or with a pre-apprenticeship course at TAFE, then work your way up and specialise in different areas.
A lot of Aircraft Mechanics progress on to be qualified licenced engineers. To work as a qualified Aircraft Mechanic, start an apprenticeship with an established aircraft maintenance company or an airline.
All positions require you to obtain an airport ASIC security ID and an Airside Driver’s License. The CASA website has lots of info on how and where to gain the qualifications and the experience needed to be licenced in the industry.