Mazatrol is your friend. Push the button to turn the spindle on. If you just booted up the RPM will be 0. It will hold 0 and not allow you to turn it. Use the button to raise the rpm. Select axis with knob? And push feed button as x1, x10, x100, or something like that. Push soft key for COMMAND screen and control will show big numbers. Use arrow keys to highlight any axis numbers you want and type in a number like 0 and handwheel will feed from there. More or less like that. I cannot repeat it because I do it without thinking about it.
MDI has nothing to do with what I listed above.
You can also feed by pushing any axis +- button and I sometimes do that when I want to face a long piece in a single pass. I can do it, but forget how.