Partizipien anstelle von Nebensätzen
Participles - "having + past participle" and "after + -ing"
When one action happens before another action in a sentence, then you have to use "having + past participle (3rd verb form) for the first action. However, you can also use, "after + -ing" and it will mean the same thing.
After John had finished his breakfast, he went to school. (First John eats his breakfast and then he goes to school)
Having finished his breakfast, John went to school. (Don't forget to mention the name of the person in the main clause, if given).
After finishing his breakfast, John went to school.