Responsive Slider Plugin HELP

I have the newest responsive 20/11 theme and I just added the responsive slider plugin, from there I went to slider in the admin, settings and adjusted the width and height. Now the “add slides” settings I’m confused, it’s asking for a URL link instead of just upload images. I want the slider to appear in the header of the landing page using the default header images provided by the theme. How do I go about doing that, what URL should I use and where to paste the php code to pick up the slider in header php? Please help me.