Counting the Omer is the commandment to count 50 days (seven Sabbaths plus one day) between the offering of the first fruits of the barley harvest (often called First Fruits) until the feast of Shavuot (Pentecost) (Leviticus 23:15-21.
Scripture was written to a people living in an agricultural society with a functioning Tabernacle or Temple. Today, most of us do not live this life. The Temple has not been rebuilt. Of course we could just forget this command or seek to pursue it in the best way we can. We prefer the later. In the year 2018 the Counting of the Omer began on April 1st. The downloadable pdf file lists scripture readings for each day leading up to Shavuot.
For additional teaching on Counting the Omer Mike has a recorded message available from the AUDIO RESOURCE PAGE