Figure out the formality level first
Polish clearly distinguishes between Cześć, used with people you know well, and Dzień dobry, used with strangers or in situations that call for formality. Dzień dobry literally means "good day" and works safely any time from morning through the afternoon, so it is the safest choice when meeting someone new.
The spelling looks intimidating, but the rules are consistent
Polish often clusters several consonants together, like sz, cz, and rz, which can look daunting at first glance. Each combination follows a consistent pronunciation rule, though, so once you learn the patterns you can make a reasonable guess at pronunciation just from spelling. The phonetic guides here are simplified approximations -- pairing them with native audio will get you much closer to accurate intonation.
Frequently Asked Questions
What exactly does Proszę mean?
Proszę is one of Polish's most useful multipurpose words -- depending on context, it can mean "please" when making a request, "here you go" when handing something to someone, or "you're welcome" in reply to thanks.
Is Cześć okay to use both when arriving and leaving?
Yes -- Cześć works as both a casual hello and a casual goodbye among people you know well, similar to how "hey" or "bye" might work informally in English.