1. Punctuating Adverb Clauses
Rule #17
Punctuating Adverb Clauses

2. Subordinating Conjunctions
Subordinating conjunctions connect clauses together to make complex sentences.
Usually, they show some sort of a condition or relationship between two ideas (time, place, condition, cause)
Examples – because, since, after, while, although, if, before
Subordinate conjunction + sentence = adverb clause

3. Usage
When starting a sentence with an adverb clause, it must be followed with a comma.
After Mr. Krogmeier brought his son home, every minute of sleep was precious.
No comma is used when the adverb clause is in the middle of the sentence.
Every minute of sleep was precious after Mr. Krogmeier brought his son home.