You are fortunate indeed to be spending time in Poland. I spent several months there for my job. For what its worth, here are my observations on language in Poland
Before heading over, I knew English, French, some rudimentary German, but no Polish. It is a hard language to speak (even harder to read). It also bears little in common with the Romantic or Germanic languages. I was told to focus on learning vocabulary. I carried flash cards with words/phrases all the time, trying to learn 25 new words a day.
It really helped to be able to point to something and name it. Eventually, I learned how to string some words together with phrases such as “where is?” and “How many?”
Learn the phrases the help establish civil interactions, “Please, thank you, Hello, Goodbye, “ etc. It will show you are trying to respect their language and culture, and it will open many doors. Most Polish people I interacted with spoke at least basic English, and once they find out you are not German nor Russian they will likely want to try out their English.
The Polish people I met were friendly and sincere. The Churches (that survived the German/Russian occupations) are beautiful, the countryside is pleasant and the food is amazing. If you can, try to get up to north coast. Gdansk, Gydynia and the Baltic coast are fun.
Enjoy your time in Poland! Dobre zdrowie!
But remember also to distinguish between formal and informal for “you”, just as with “usted” in Spanish versus the informal “tú”.
Formal Polish uses “pan” for male and “pani” for female, versus “ty”, the informal “you”.
“Cześć” is informal “hello”, but you should always use the more formal “Dzień dobry”.
Best way to really learn a language is listening to music. I became a big fan of Polish music that way. It helps to recall words if you can memorize the song lyrics.