My dodge cummins has hard start problem and sometimes my dash display will say Done what does this mean it says it where the mileage readout is displayed

Not sure about your hard starting problem, but the Done in the odometer is the conclusion of the computer test. If you turned your key on and off 3 times, it activates the self-diagnosis and will show the codes of any problems you are having. If you are getting no codes, and just DONE, it's finding no problem.

Maybe a Dodge expert will pipe up and give you some ideas about the no-start. According to a quick google search, it seems your problem is relatively common.

DONE...when did dodge start makeing microwaves?
The last poster is right about the self test and display. If this does not go away after disconnection of batts, you need pro help. the VECU bricked...sorry