Translation of commandant in Spanish

Hello, I am John, I'm 29 years old, I have lived in Heidelberg all my life, I have a son and I am working at Lenzemanner in the South of Germany since 1980. I look forward to hearing from you.
Please explain me the exact differences between British and American .... This year I'm trying to make the TOEFL. We can then discuss how we can prepare for this exam. I failed the first time.
Great that you've written me back so quickly. I want to be your pen pal and we could help each other. I am looking for people who could help me learn Spanish, with focus on conversations.