Question on Customizer-Child theme!

Guys,

I have created a child theme for Customizr but whatever I add to the stylesheet.css of my child theme, I don’t see any changes.

My child stylesheet begins as follows:
———————
/*
Theme Name: Customizr-Child
Version: 1.0
Description: A child theme of Customizr
Template: customizr
*/

@import url(“../customizr/style.css”);
————-

Two questions:

1) What do I need to do to make my child theme work?

2) Also, I copied and pasted class-header-slider.php file from the “parts’ folder of Customizr into my Customizer-child folder to make some modifications to it but I got an error message.I have to remove it again.
Any idea what I need to do?

Thanks!