Now that your full of knowledge of what Purgatory is and how to help the holy souls there, where do you go from here? This book, as its title implies, is an introduction to Purgatory, a first course. Its by no means the final word on the subject as there is still much to learn after this.
There are many books and other resources where you can discover more about Purgatory. While its important to learn more, you have to keep in mind the main purpose of studying this topic: you want to help free the holy souls from Purgatory so they can enter Heaven. The key to success here is a consistent devotion. Choose something that you can do regularly and every day if possible.
The holy soul that you pray for may not have anyone else helping them. Your sacrifices and devotions are more important than you can imagine. Use your newly acquired knowledge to help your suffering brothers and sisters and encourage others to do the same.