Spanish speakers sometimes find it hard to pronounce "m" at the end of English words and it often sounds like an "n". You have to exaggerate this "m" and then it may sound more natural to us.

"then" is a word that defines a moment in time. "them" is a personal pronoun. Examples: First I ate an apple. Then I drank a cup of tea. My friends came to see me. I gave them something to drink.