Chart datum, level of water depth on a nautical chart. Datum or datum point, a (possibly arbitrary) reference baseline or point from which scientific measurements are made (from a Latin meaning of datum as a given, i.e. an accepted fact)
Music directors and composers must guide musicians and singers by preparing musical arrangements and helping them achieve the best possible sound. Musical talent. To become a music director or composer, one must have musical talent.
You need to buy licenses from ASCAP, BMI and SESAC who will then pay the owners of the copyrights in the musical composition [the words and music] for the songs that you play in your establishment.