The Omer is counted every evening after sunsent, from the seance night of Passover until the night before Shavuot.
One stands and begins by reciting the following blessing:
BARUCH ATAH ADONAI ELOHEiNU MELECH HA’OLAM ASHER KID’SHANU BEMITZVOTAV VETZIVANU AL SEFIRAT HA’OMER.
Blessed is the mystery that flows through time and space. You infuse us with holiness and call us into connection trough the counting of the Omer.
After the blessing, one recites the appropriate day of the count. For example:
Hayom yom echad la’omer
Today is the first day of the omer.
After the first six days, one also includes the number of weeks that one has counted. For example:
Hayom sh’losha asar yom, she’hem shavuah echad v’shisha yamim la’omer
Today is 13 days, which is one week and six days of the omer.