Hello devos, lets see what we can do here!
Firstly download and install TTools by Lee Swordy(i think) as most ai traffic programmes use this to install the flight plans.
Next choose tha ai programme of your choice (i use projectai so i'll describe how to use that).
Download and install the installer to a folder where you can easily use it.Now find the Quantas full ai package and download and unzip that to a folder of your choice.
Go to the projectai installer and double click on it then in the search box go to the quantas ai file that you have just unzipped and click open and just follow the instructions of the on screen install setup and it will install the aircraft and flight plans into FS2004 for you.
Hope this helps 😀 .