Yes, I have direct experience of this. It was simultaneously the most harrowing and rewarding thing I've ever done in my life (the perpetrator was sent to prison for 7 years and wasn't allowed any further contact with his young stepchildren). I reported some years ago, but the procedure in my case went a bit like this:
My mum called the police when I disclosed (was only 18), they came round the next day and interviewed me. I gave further evidence at a safe house a few weeks later, and had to go round in an unmarked police van to point out relevant locations to them. He was arrested shortly after, and statements were taken from anyone I had disclosed to in the past (friends, school, church leaders).
After the evidence had been gathered, the CPS examined the case and determined that there was enough evidence to go forward to trial at the crown court. He had several initial hearings that I didn't attend, and was in custody because he broke his bail conditions.
About 15 months after I first disclosed, the case went to trial. I gave evidence via video link due to my age/poor mental health. The other witnesses and the perpetrator gave evidence in court. I spent most of my time in a special waiting room for victims run by Victim Support. The trial lasted about 8 days, and my evidence made up about 1.5 of those days. I didn't go into court to hear the verdict, but I did about 4 weeks later to hear the sentencing.
The police were very much on my side and did all they could to secure a conviction, but the process was still very difficult and left me with further health issues. I don't regret it though. If you have any further questions, please send me a message and I'll try and help you x