Hi Benoît,
I can understand you now! :)
Yes, it's about the suffix I mentioned before and what you might have seen in the video at 2:30. They called it agglutionation. From wiki: "the term agglutination is sometimes used more generally to refer to the morphological process of adding suffixes or other morphemes to the base of a word."
Let's stick to the word: Work / Munka (which is the base word) and I'll tell you the variations for different cases.
My work : (sok a) munkám
Your work: (sok a) munkád
Her/His work: (sok a) munkája
Our work: (sok a) munkánk
Your work: (sok a) munkátok
Their work: (sok a) munkájuk
*
As you can see these additional tags deffine whose work it is. Since I'm not a grammar teacher (in fact I'm not teacher at all) for deeper explanation and rules you should take a Hungarian lesson from a professional teacher ;)