George Florea Banus

Did you install and activate the JP Widget Visibility plugin?

No, no sound.

See here:
https://www.youtube.com/watch?v=av0Z2jLnlRc

If you didn’t touch the core wordpress files, it shouldn’t break anything, do make a back-up before.

I recommend you set up a localhost and duplicate your site and test it first to be sure.

https://managewp.com/how-to-create-a-local-copy-of-a-live-wordpress-site

I see the theme already has a sidebar, so go to /wp-admin/widgets.php and add a widget to the Blog Sidebar, either a text sidebar and create the links manually like <a href="page_url">page title</a> or you can create a custom menu at /wp-admin/nav-menus.php and add the custom menu widget and select the menu you just created.

To display the sidebar on a single page you can use JP Widget Visibility, this will add a button to your widgets “visibility” that will allow you to choose where and to whom you want to show the widget.

You access the file in your browser.

If you’re working on your pc you need to set up a local server like xampp, if you’re on windows.

Then you copy the wordpress files in the right folder of the server you installed (for xampp that is C:\xampp\htdocs\ , best create a folder “wp” there) and then you go to https://localhost/wp/wp-admin/install in the browser

Would help if you could share the site and maybe the active plugins and theme.

To install you copy the wordpress files to a folder and then you go to

your_address/wp-admin/install

and you should get the installation page, this is where the wp-config-sample.php file is needed, if you edit/create the wp-config.php manually you don’t need wp-config-sample.php.

How do you know which country the user belongs?

If you have a custom field you can use an if else statement:

if(custom_field == 'Country A'){
    // code for Country A
}
else if(custom_field == 'Country B'){
    // code for Country B
}
else if(custom_field == 'Country C'){
    // code for Country C
}
else if(custom_field == 'Country D'){
    // code for Country D
}