It is explained in the pdf manual installed with MEP it is in the Start menu , Programs, Movie Edit Pro, Documentation folder. Look under the Burn section.
For NTSC select the settings you need as shown in his image
Standard DVD video format is mpeg2. At the optimised settings you get approx 2 hours video on a single layer DVD.
I would only use mp4 for HD burned (as Bluray) to standard DVD's - you can get about 30 - 40 mins on a single layer DVD and it will play in a Bluray player.