Customising the theme

[gagandeep995]

I am using the theme for my project bu facing some issues.
One major one is:
1.If I try to customise(say add) in the theme say add dynamic urls for social media in the settings section and try to get that in the controller say
Webcore\Page\PageController@index and then if I try to work with another package and run composer install all the changes disappear(which is obvious)
So my concern is how can we customise and extend the theme?