It's a prayer that honors the Virgin Mary and seeks her intercession. The precise timing of when it is actually prayed may well vary based upon individual or Group tactics. The hymn is sung (using the English translation "Hail, Holy Queen enthroned higher than") by a choir of nuns from https://encapsuladosvip.com/vita-pro-nobis-descubra-os-beneficios-dessa-incrivel-planta-medicinal/