It's a prayer that honors the Virgin Mary and seeks her intercession. The particular timing of when it is prayed may well differ depending on specific or community techniques. The hymn is sung (using the English translation "Hail, Holy Queen enthroned over") by a choir of nuns in the 1992 https://encapsuladosvip.com/vita-pro-nobis-descubra-os-beneficios-dessa-incrivel-planta-medicinal/