Subscriptions are not working well for me

Good afternoon everyone. We attach a pdf file, with information about the subscriptions, since it is not working as it should, we can not find more extensive information that allows us to correctly implement the subscriptions, so that the client can see the statistics, of the articles that are sold the most , or how much storage is left in MB, according to the configuration that is made. Thank you in advance for how you can help us to carry out this part in a satisfactory way.