Yes! I have that book. It is extremely good -- very informative, very inspiring, very beneficial!
Oh good, someone else has read it. I am going to try to remember some ideas from it since the OP may find it helpful. You can correct me if I get anything wrong.
The book Frequent Confession
is about going to Confession every week or so and confessing venial sins. It is not for people who are committing mortal sins frequently. Confessing mortal sins is a straightforward subject that most Catholics understand.
There are certain challenges associated with confessing venial sins. For one, many people do not understand that it is of great spiritual value. Even though it is not strictly necessary it can lead to much spiritual growth. For another, it can be difficult to develop proper contrition for these sins due to the tendency to try to dismiss them as "only" venial. Yet another challenge is that venial sins are often habitual sins and this can lead to discouragement when one keeps confessing the same thing week after week.
The author recommends giving a lot of attention to the purpose of amendment. It should be very specific, not a vague "I'll try harder." He says to pick one venial sin to focus on. (Unlike mortal sins, there is no obligation to confess all the venial sins one can remember.) If it is a habitual sin, don't be discouraged but keep coming back to confess the same sin because this will give access to the graces needed to conquer it.