Here's a breakdown of the pronunciation:
* cz: pronounced like the "ch" in "church"
* e: pronounced like the "e" in "bed"
* ść: pronounced like the "sh" in "ship"
So, "cześć" sounds like "chest".
You can also use "dzień dobry" (pronounced "dzen dob-ree"), which means "good day". This is a more formal greeting.