describe their overall image, goals, values, political leanings, lifestyles, general attitudes towards their country, parents, religion, etc.?
Polly don't be such a lazy lump. There are plenty of sources for this information and as it's obviously going to be your new obsesssion for a while you'd better learn how to research it yourself. If you're prepared to read articles about young Europeans in general you can find little nuggets of information about Polish millennials. I managed to glean that:
Millennials comprise 28% of the Polish population.
In 2014, over half of Polish millennials reported being satisified with their lives compared to just over 30% of those aged 50 and over.
Only 12% of Polish millennials believe that Russia respects the personal freedoms of its people.
Only 12% of young Poles have respect for Vladimir Putin as a leader and international statesman.
One in three Polish millennials cites getting a good education as very important in achieving success in life.
But only 25% of them think that working hard is very important to get ahead in life.
63% of Polish millennials believe that 'success in life is pretty much determined by forces beyond our control'.
Here's another survey which is easily digested:
Some info on religion here:
That should keep you nicely occupied and out of mischief for a while. Let's see what you can come up with on your own now, there's a good boy :)