Use a comma after "later" when it introduces a dependent clause:
* Example: We'll discuss this matter later, when everyone has arrived.
Do not use a comma after "later" when it acts as an adverb:
* Example: We'll discuss this matter later today.
Here are some additional tips:
* Think about the flow of the sentence. If you pause slightly after "later," you likely need a comma.
* Look for a dependent clause following "later." If there is one, a comma is usually necessary.
* If "later" modifies a noun or verb, no comma is needed.
In general, it's best to err on the side of using a comma after "later" if you're unsure. It's better to be slightly formal than too casual.