im very new to database world and i would like to start learning the staff

i have chosen a topic, which is CMS(Content management system), want to start with a simple cms like wordpress or These kind.
my problem is that as im new to data base, i dont know what elements of a topic could be used in a data base design and im trying to understand it this time

i gathered cms system analyze from some articles like This one(but alot simpler than this article i.e wordpress) and i red it all but i dont know what of it could be the elements of a database and i need some help in the analyze

Please guide me what to do?