You've basically outlined your entire database project. What Specific parts of that project do you want help with?
Thank you for your quick answer.
To begin with, I want to be able to create a field in which the payments of the current month per community are displayed. This field needs to be automatically updated every month. Having this, I want to create another field in which all monthly payments per year are summarized (so not total, only payments of 2013).
Thanks in advance!