Later and Then

Later adverb - Following in time or place.

Then is a synonym for later in subsequently topic. In some cases you can use "Then" instead the word "Later" as an adverb or an adjective.

Then adverb - In addition to what has been said.

Later is a synonym for then in next topic. You can use "Later" instead the word "Then" as an adverb or an adjective, if it concerns topics such as before.