Can somebody tell me what IFR is and how I can use it because I hear ai planes in the game always get nice instructions via the radio but I can't get them.

WHY ?? WHY ???

IFR = Instrumental Flight Rules.

It means you follow your instruments rather than VFR, which is Visual Flight Rules.

y2cragie gave you all the useful information already, though! Click Flight Planner on the main screen, select a departure airport, and then a destination airport. Then click IFR instead of VFR, and choose high-altitude airways, low-altitude, VOR to VOR or GPS. Most of my IFR flights are high-altitude ones.

Then you just need to click "generate flight plan", or whatever it is. The ATC will then give you every instruction you need (with the exception of telling you how to fly the plane!) to get from A to B.

A VOR (Very high frequency Omnidirectional Radio) is like a marker in the ground. These VORs in the ground will have radio frequencies that you can tune into the NAV radios on your plane, and once you're "tuned in" to a VOR, you can follow some dials on the panel of the aircraft to tell you exactly where to go to reach this VOR.

Flying from VOR to VOR without the use of the GPS system is a lot more difficult than just getting up there and putting on autopilot, but it's twice as rewarding!

thanks and now I've taken some VOR lessons but stil how can I choose witch "radiopost" I need to take me to my destination?? and how do I make contact???