Short answers, pulled from the story.
The Duke of Medina Sidonia commanded the Spanish Armada in 1588. He was a man who had never commanded a ship before being appointed by King Philip II of Spain after the death of the original commander, the Marquis of Santa Cruz, in February 1588.
The English fleet engaged the Spanish Armada off Gravelines at dawn on the 8th of August 1588. The battle lasted for eight hours, during which the English fired damaging broadsides into the enemy ships while maintaining a windward position.
The Spanish Armada fleet consisted of 141 ships when it set sail, carrying 10,138 sailors and 19,315 soldiers. The fleet was a motley collection of 24 purpose-built warships, 44 armed merchantmen, 38 auxiliary vessels, and 34 supply ships.
After the battle at Gravelines, the Spanish fleet sailed north around Scotland and Ireland to return to Spain. Many ships were lost to storms and shipwrecks along the west coasts of Scotland and Ireland, with about 5,000 men dying by drowning, starvation, and slaughter by local inhabitants.
The Spanish Armada failed to invade England because the English fleet utilized superior tactics involving cannon fire from a distance and the weather gage. The Spanish determination to fight by boarding rather than employing cannon fire at a distance proved a disadvantage, and the fleet was scattered by English fireships off Calais on the 7th of August 1588.