Hi,
well there is no best/ easiest program, is actually which do you prefer to use. All authoring software should have the basic functions, some of course have more functions which you may/may not need. So if the program comes with a trial version perhaps it is worthwhile to test them out before buying them.
We have some guides at
http://www.dvd-guides.com/content/category/3/69/77/ perhaps you would like to refer to them
There is another program which if i am not wrong is freeware, DVDAuthorGUI, check it out.