Participle clauses express condition, reason, result or time.
Here are some examples:
Condition (used instead of an ‘if’ condition):
Looked after carefully, the new smartphones will last at least three years.
(If you look after it carefully, the new smartphones will last at least three years.)
Reason (used instead of linking words like so or therefore):
Having studied French at school, he was able to travel easily around Paris.
(He studied French at school so he was able to travel easily around Paris.)
Result (used instead of linking words like as a result or because):
Having no internet connection, John decided he would read a book.
(John read a book because there was no internet connection.)
Time (used instead of time words like while, when or as soon as):
Working on his project, John suddenly remembered he had promised to telephone Susan.
(While John was working on his project, he suddenly remembered that he had promised to telephone Susan.)
You can also emphasise that actions happened in a sequence (one action was before another) using the perfect participle (having + past participle):
Having locked the door, John walked to his car.
1st action: lock the door
2nd action: walked to the car
Participle clauses with past participles have a passive meaning:
Shouting loudly, David ran into the room. (David was shouting)
Shouted at loudly, David walked home. (Someone was shouting at David)