COMMA #2
Use a comma after an introductory adverbial clause,
verbal phrase or absolute phrase
Introductory adverbial clause
When Rick finished the marathon, he was exhausted
Introductory participle phrase
Being late, I could not eat breakfast.
Introductory infinitive phrase
To enter the contest, we needed a number.
Introductory gerund phrase
For making the arrangements, Bob was given a bonus.
Introductory absolute phrase
My ticket having been punched, I took a seat on the bus.
Use a comma to set off nonessential appositives
Jean, the head cheerleader, was the smartest girl in school.