Later means a time following or after a given time.Some time in the future, rather than a sooner identified time.
Ex - Sooner or later, everyone catches a cold.

Later can also be used informally as a way to say goodbye.
Ex - I have to go now, but I will see you later.

The meaning of latter is something that is closer to the end of something than to the beginning of it.
Ex - The latter part of the movie was my favorite.

Latter is also use to identify the second in a list of two things. Now for a few examples of latter used in this way.
Ex - Between the two choices, I would rather have the latter than the former.