I'm student still practicing this software, i have a plc at home, thinking about setting some projects up using nodered as a HMI, through my phone preferably.
Does the CMD have to be running (online) for me to use nodered dashboard?
If not then how can i make it stay online without my computer being online 24/7?
The dashboard is being hosted by Node RED, therefore Node RED has to be running.
if you don't plan on keeping you computer running 24/7, you will need to invest in a small raspberry pi type computer to run Node RED 24/7.
and of course, if you plan on accessing it remotely (via your phone), you need to setup some kind of secure access to the dashboard - there are quite a few examples in here.