Begin by saying the following prayer each evening of the count:

BA-RUCH A-TAH YHWH E-LO-HE-NU ME-LECH HA-OLAM ASHER KID-E-SHA-NU BE-MITZ-VO-TAV VETZI-VA-NU AL SEFI-RAT HA-OMER

Blessed are You, YHWH our Elohim, King of the Universe, who has sanctified us with His commandments, and commanded us concerning the counting of the Omer

Hayom e-chad v’esrim yom, shehaym shlosha shavuot la-omer

Today is twenty-one days, which are three weeks of the Omer