Here is a step by step iDVD tutorial on how to create a simple, home authored DVD with the OneStep DVD feature.
What is great about Apple's iDVD is that it takes the mystery and skill out of DVD authoring. For most people, DVD authoring seems like a complicated part of the post-production process that should be saved for professionals. Even DVD authoring software like DVD Studio Pro, which makes it practical for people to produce professional looking DVDs, is far too difficult for the uninitiated. With iDVD they can take care of simple DVD authoring projects without much skill. If you just want to make your own incredibly basic DVD that will just play your movie file then iDVD includes a great function for this: OneStep DVD. Here is an iDVD tutorial on how to create this almost instant DVD project using the OneStep DVD function.
What the OneStep DVD process will do is produce an auto-play DVD without any real menu systems or controls in place. This is not going to feel like a complex DVD authoring process, but it will be great to preview footage or turn something in for a class project or presentation.