Well one must make some assumptions here....we will assume you are working on MEP14,15,or 16. It is the same process on all of these so....

Save your project.
In he upper right corner beside "edit" is the "burn" tab. Press this and insert a dvd in the burner.
Choose a menu for your production and click the "burn" button on the right.
Follow the instructions .

The program should set most of the required setting automatically so just press the "burning disc icon" and let it go....expect a few hours.