Not 100% sure with Austria. But I believe it's similar to Germany (I'm currently finishing my paperwork to start residency here).
I will describe the process in Germany and hope that might help you.
You need to get an Approbation in order to practice medicine. For this you need
1) Language requirement via a test called Fachsprachprüfung (oral doctor/patient and doctor/doctor communication skills inGerman)
2) General medical test called Kenntnisprüfung. Imagine Step 2CS and CK but it's oral and in German obviously.
After passing both tests you get the license and can apply to a residency spot. There is no matchmaking or ranking system. You just go to any hospital with a vacancy and apply for employment.
Residencies last for at least 5 years (can take up to 7 or so) and sometimes you have to switch to another hospital to continue your training. It's an open end system. After you meet certain requirements you can apply for "board certification" to make an analogy
The hardest part is the language barrier. It took me around 10 months to go from no german to B2-C1. The Fachsprachrpüfung is based on C1.