How did Spain become a colonial empire?

Spain became a colonial power because of the search for a sea route to India. By 1492, the alignment was as follows: trade routes from Europe (along the Mediterranean Sea) were blocked by the Ottoman Empire and the Mamluk state, so the Spanish king Ferdinand II in 1492 sent Columbus to the west, and he found the islands of the Caribbean Sea instead of India. In 1496 the Spaniards founded Santo Domingo, and in 1519-1522 they conquered the Aztec empire in Mesomerica, 10 years later the huge Inca empire. Thus, by the middle of the 16th century, a colonial empire was formed, from the border of the modern USA and Mexico to Argentina. Also, the Spaniards took control of the Philippines.