Short answers, pulled from the story.
The Cantabrian Wars lasted from 29 BC to 19 BC, with minor rebellions continuing until 16 BC. They marked the final stage of the Roman conquest of Hispania, a process that had taken roughly two centuries in total.
Augustus moved to Segisama, in modern Burgos, in 26 BC because earlier Roman campaigns had failed to truly subdue the Cantabrians and Asturians, despite receiving official triumphs. The Cantabrian Wars were one of only two wars Augustus directed in person against barbarian peoples, the other being his Illyrian campaign from 35 to 33 BC.
Rome deployed eight legions plus multiple auxiliary units, totaling at least 50,000 soldiers, with some estimates exceeding 80,000 when the naval forces from Gallia Aquitania and full auxiliary strength are counted. The legions included the I Augusta, II Augusta, IV Macedonica, V Alaudae, VI Victrix, IX Hispana, X Gemina, and XX Valeria Victrix.
The Cantabri relied on guerrilla warfare, using their knowledge of the mountainous terrain to launch surprise raids on Roman columns and supply lines before retreating quickly. They were equipped with short swords, daggers, javelins, wooden shields, and the bipennis, a double-headed battle axe. Their cavalry tactics, including the circulus cantabricus and cantabricus impetus, were later adopted by the Roman army.
Roman forces under general Publius Carisius drove Asturian forces to the hillfort of Lancia and then to Mons Medullius, which some scholars identify as Las Médulas. The Romans built a fifteen-mile-long moat and ditch around the mountain to besiege it. Rather than surrender, many defenders chose death by their own weapons or by poison made from yew tree seeds.
Rome stationed two legions, the X Gemina and the IV Macedonica, in the region for seventy years after the main fighting concluded in 19 BC. Local resistance was significant enough that minor rebellions continued until 16 BC, even after the major military campaign was over.