Uses of the participle

To form the continuous tenses

The present participles are used to construct the continuous tense forms.
I am writing.
They are coming.
It was raining.
She will be sleeping.

To form the perfect tenses
The past participles are used to construct the perfect tense forms.
He has written a novel.
The boy has broken yet another window.
The baby has slept for three hours.

The past participles are also used to form the passive voice.
They have been invited.
This house was built by my grand father.

To qualify nouns or pronouns
Participles can be used to modify nouns or pronouns. They may be used:

Attributively (before a noun)
A rolling stone gathers no moss.
A lost opportunity never returns.

Predicatively (as part of the predicate)
He kept me waiting.
He looked worried.

The participle may also be used absolutely with a noun or pronoun going
before it.The weather being fine, we went out.
God willing, we shall meet again.
The sea being smooth, they embarked on their voyage.

Note that in the sentences given above, the participle with the noun or
pronoun going before it forms a phrase independent of the rest of the
sentence. Such a phrase is called an absolute phrase. A noun or pronoun so used with a participle is called a nominative absolute.

An absolute phrase can be easily changed into a subordinate clause.
As the weather was fine, we went out.
If God is willing, we shall meet again.
Because the sea was smooth, they embarked on their voyage.