no worries.
before diving into modifying power store though, I would recommend getting familiar with security assist in a blank site with blank db.
Create a new site to fool around with security assist and go through the tutorials on the security assist support page, even the ones in the how to section.
Once you are comfortable with using security assist to create the login pages, then it will be easier to get into modifying power store.
I always find it easier to learn how to use a new tool when you aren't trying to modify something that has already been created.