What is the difference between boosting engagement and links when you use Facebook advertising?

My wife recently published a historical novel. He receives very good reviews and I try to promote beyond what his publisher does.

I've already tried to boost engagement and clicks on links using the Facebook advertising platform. Ideally, I want to lead people to his website so that they can read the first chapter of his book, sign up for his newsletter and be directed to a place where they can read it. 39; buy. However, I also wish to strengthen its presence on social networks as a secondary objective.

Promoting commitment at first sight seems very effective. Nearly 50% of the "affected" people engage with the job. However, my web logs show me that very few people are accessing the website. Facebook deletes links by clicking when optimizing the engagement? Or do they choose the kind of people who love everything without clicking anything?

What's really going on under the hood?