Hello,
I’ve got some questions about the Grav core… in my modular page which I want to collect some of my posts by popularity. Is it possible? in Grav core when the pages are visited are they also going to be counted by Grav? and if they are, how could I collect them in my pages? thanks 
This is not possible via the grav core because popularity is provided by admin, and the data is stored outside of pages, in a separate file. You would need to provide a function via a plugin that could sort an array of pages by looking in the popularity file and determining order.
thaxx