Euh,.. POSKY doesn't have a 319, maybe you mean IFDG.
Anyway ,1st make sure you have winzip, unzip your file with the wizard interface.
All files will appear in a subfolder in the C:/unzip folder.
You need a model folder, a sound , a panel and a texture folder.
Also you'll see an aircraft.cfg and an air file, in the aircraft file (open with notepad) you'll have a section that says "ui_manufacturer=xxx" the xxx will be the name under witch the aircraft will appear in the drop down selection menu for the aircraft in the game.
I also advice you to download a panel and a good sound file so it will be more realistic.
for some excellent AIRBUS models make sure to look for HNAC (A300-310),
Aerodesigns (A300,A318,A340) and Flightcraft (their wonderful A330).
For panels I advice Recommend Simon Topmans panel for the A300-600 and A310, Benoit Gaurant's panel for the older A300 models.
For the A320 family and the A330-340 I advice you to look for Eric Marciano's wonderful panels and last but certainly not least if you decide to download the aerodesigns 318 and 340 they have standard panels (with vc) and I must say they are almost payware quality (except FMC) certainly when we're talking their 340 series.
More questions don't hesitate to ask.