Hi, Krzysztof,
This plant is in the family Saxifragaceae,and usedto be called Mukdenia, I think.
I do not grow this plant but if I were to buy it I would plant it in a place with moist , rich soil ( with quite a good amount of nutrition in it) and, here in Aberdeen and I think for you in Poland, I believe it would quite like a spot that was sunny for a few hours a day. I think in warmer, sunnier countries it would like shade for longer each day! Certainly this type of saxigragaceae plant likes a warmer position in Aberdeen, but with a moist soil .