Add the "Edge ISO Images" page the the "installation guide", or reference it.
I think the page about the Edge version should be in the "Installation Guide" (or linked) https://github.com/linuxmint/doc-user-guide/blob/master/docs/edge.rst
I think the page about the Edge version should be in the "Installation Guide" (or linked) https://github.com/linuxmint/doc-user-guide/blob/master/docs/edge.rst