I have done PE therapy, twice. it was INCREDIBLY helpful--it drastically reduced my PTSD symptoms and made it possible to address the trauma in a way nothing else we had tried did.

It took me a looooong time--months of weekly sessions--but the time varies for people and what they are working on. Here's what I did with my therapist over the course of many weeks:

First, we did lots of relaxation work. I created a safe place and T took me through guided imagery to get there.
I wrote a short list of memories that were bothering me with flashbacks.
We grouped some of the traumas together (like 'all the times he did X') and I picked the worst memory.
We numbered the traumas from least disturbing to most disturbing.
We discussed how to rate my anxiety on a scale of 1-10.
We started with the least disturbing memory. Sometimes I could talk through it, and sometimes I had to write it and T would read it aloud.
When I reached our pre-arranged anxiety rating (originally it was 5, but I was so poor at identifying it before it got bad that he switched it to 3), we stopped and did the relaxation.
Then when I was relaxed again, we would go through the memory again.
We repeated this over and over with each memory until I could tolerate the whole thing.

T and I did this both with memories and with real-life exposures (having to see my abuser). For that, we started with me thinking of his name, imagining passing him on the street, imagining being near him, etc. We did this because my abuser is a family member that I can't always avoid.

In the end, there were some aspects of my trauma that even PE couldn't touch, my anxiety was too high. But I am a totally different person after that work. The key is to go slow slow slow and to talk with your T about everything you are thinking and feeling. I always try to rush things and that's not how PE works!