And welcome to the Polish Forums.
Like Spain I am sure, Poland has many different traditional customs from different regions.
So for an example, Zakopane, highlanders in the south of Poland, 100 km south of Krakow in the Tatra mountains have these kinds of costume:
And here are some from Krakow: poland zakopane dress
traditional embroidered woolen costumes with their characteristic parzenica motifs.
I don't know if you want any particular region's costume or just an example but perhaps for your project you could take several examples and compare and contrast them.