Parsley (or any other vegetable such as celery or potato) is dipped in salt water and then eaten. The parsley symbolizes both the humble origins of the Jewish people as well as the rebirth of spring, which is starting now. (In Eastern Europe, where green vegetables were not common, a potato was used instead). The salt water symbolizes the tears shed during our slavery.
Before eating the vegetable, recite the following blessing:
Barukh atah Adonai Eloheynu melekh ha-olam Boreh P’ree Ha’adamah.
Blessed are You, Lord our God, King of the Universe, who creates the fruit of the earth.