Structure: Perfect Participle is used by adding (having) before the past participle (Partizip II) of a verb.
Ex: having spoken, having eaten, having known
Usage: To indicate a completed action then continuing the sentence by showing the effect of that completed action at most cases or changing the conversation's topic
Ex: Having understood the perfect participle Denis can go on with his studies.
Ex: Having spoken briefly about environmental issues Jack returned back to the main topic.