When and how to use a Past Participle ?

I hope you understand and explain

in English the verb has three forms the infinitive, the past and the past participle

for example the verb : write

the infinitive is the normal form of the verb in this case write the past tense of this verb is wrote and past participle of the verb is written.

Simple past is used when a person performed an action completely and was not interrupted or the like.

The past participle or past participle, simple is accompanied by an attendant.

Auxiliary variable that varies why?

Pay close attention :

when you want to talk in present perfect have to use the past participle of the verb plus auxiliary in this case would be present perfect have and have

have for the first person and third person has to.

Then the structure would be perfect for this :

the subejo + have / has + past participle of the verb + complement.

If you want to talk to the past perfect, the auxiliary switch, of have / has had becomes

that had applied to all subjects.

Then the structure would be perfect for the past :

sujecto + had + the past participle of the verb + complement.

The present perfect is used to narrate events that have already occurred in an unspecified time

past perfect is used to narrate events that have already occurred in the past and may continue in the present.

Some examples of the past simple, past perfect and present perfect.

Past simple :

sujecto + the past simple of the verb + complement

I ate a pizza yesterday in the morning = pizza I ate yesterday morning

she went to my party = she went to my party

past perfect :

the subject + had + past participle of the verb + complement

I had been in her house it was raining = Because I had been at home because it was raining.

She had eaten in the restaurant rice = rice she had eaten at the restaurant.

Present perfect :

I have seen him in the pool = I've seen it in the pool or I have seen him in the pool

Travelled to London she has = she has traveled to London

I hope you find a little understood.