Why did the british empire take over Spain?

Answer 1

The British Empire never took over Spain. It did, however, establish one small outpost in the south of Spain on the Rock of Gibralter, for military purposes, to be able to exercise some control over ships travelling through the Straits of Gibralter.

Answer 2

You have a very strange understanding of history. The British Empire did not exist in 1492 when Cristobal Colon discovered the Americas; colonists after his time included Dutch, French, Spanish and English. The first settlements in New England were established by Puritan exiles who chose to leave Britain.

America - in the sense of the USA - did not exist until after the American colonists severed all ties with Europe and started to expand westwards. It was therefore the Americans who took over the land that became the USA, not the British.

Lewis and Clark were not British; the Mormons were not British; the California miners were not British; the mountain men were not British; Daniel Boone, Davy Crockett and Kit Carson were not British. They are some of the people who "took over".