What do I enter for "On the Network"?

Hello, I am trying to install Red Hat Enterprise Linux 7 as a VM. While Installing, I get the error that Installation Source can't be found. I'm trying to use the Download ISO in my Downloads. After clicking on the Installation Source button I get to a page asking for a URL (On the Network.) What do I enter for the URL? Is there another way to use the ISO? I tried Mounting it but it still doesn't work. I have not burnt a DVD yet. What do I enter for the URL? Please respond. Thanks