Run Ubuntu No Monitor

I would like to run an Ubuntu (18.0.4) desktop with no monitor/keyboard attached, and access it via VNC (or Remote Desktop) from a Windows 10 Pro machine. I have installed VNC Viewer on Windows and enabled remote access from Linux. It all works, but not until I log on to the Linux box from an actual keyboard - which defeats the purpose. In other words, Linux will let me log in remotely only after I am logged in physically. I followed instructions to set up Linux for remote access , including the bit about "allowing unencrypted connections", but then I realized that those are instructions for allowing an external user to view/control *the same session* as a logged-on user, as opposed to allowing an external user to start their own session. What do I need to do to have the Linux-side start up and be ready for connections without the need to attach a physical keyboard? For instance, perhaps I need to make sure that VNC Server starts as soon as the Linux machine boots, etc. It does not need to be VNC. I can work in the Windows remote desktop window as well. I just want to access this Linux machine without attaching a keyboard/mouse/monitor.