Svg color API documentation is poor

This documentation is so poor, please tell about the exactly procedure about how to use it step by step.

I just want to change the color of #Appmenu in the top bar, are SVG files but fill property doesn’t work.

Follow the guide and I have no idea how to apply the changes, I checked the files /core/css/css-variables.scss and functions.scss then go to URL mydomain/svg/files/app?color=11a6ff and get #fff SVG folder icon.

My icons doesn’t change to my desired color.