How to access variables and change its value in templates?

[patadura]

Hi community, I apologize for my bad English, I've been using Prestashop by the latter days.

I learned a lot, about the system but there are things that are loose and I can not understand well yet, a lot because I have not managed to find a tutorial on the PS core and a little because I know the basics of php.

Just need to learn how, and what variables, I can access from the tpl, and from the templates if I can make them change their value before display.

a case in point is that I need to change the value of the cover image before the template to display it. But sometimes I feel that I need to change the value of another variable and can not understand how to access them.

If I can give some help to understand how is that smarty variables or how I can get access to variables that contain values ​​from the database. It can be operated from the smarty tpl or I have to play without fail the corresponding php to send these variables to the templates.

Maybe I'm missing theoretical fit on this topic to finish to understand the core of prestashop management. Know of any manual, tutorial or give me your words can help to better understand what life is like a variable in the whole environment of the PS. From birth to death in the template.

I hope I was clear, best regards to all