The Celts were an ancient group of people who lived in parts of Europe, including Scotland, Ireland, Wales, Brittany in France, and Galicia in Spain. They lived in small, circular stone and straw houses located in villages. There are remnants of Celtic rock art and symbols found throughout these regions today, including designs seen on traditional Galician horreos. The document then provides instructions for making a wooden Celtic-inspired plate using materials like wood, paint, and acetate to cut out and apply Celtic patterns.