Complex sentence: He then served at the invasion of Isle de France, and on the coast of North America; and on 7 June 1814 was promoted to the command of HMS "Thames", in which he took part in the battle of New Orleans.
Split into simpler sentences: He then served at the invasion of Isle de France, and on the coast of North America. On 7 June 1814 was promoted to the command of, in which he took part in the battle of New Orleans.