The past participle denotes a completed past activity when it shortens a clause.
Examples of past participle
Warned of danger weather, he changed road to home.
Once done, it can’t be undone.
Once seen, it can never be forgotten.
All things, considered, it is not such a bad idea.
Told what to do, she started at once.
HAVING + PAST PARTICIPLE, HAVING BEEN + PAST PARTICIPLE
Both having + past participle and having been + past participle denote a complete activity which took place before another one in the past.
Having done all my work, I went home.
Having recovered from injury, she start running again.
Having written all my website posts, I go outside for walk.
BEING + PAST PARTICIPLE
Being + past participle denotes a completed activity in the passive, which happened before another activity.
Being informed of the danger, he decide not to take AstraZeneca vaccine.
Being sent in time, he was able to reach them.
The work being done, everybody felt pleased.