I have never used either of the Wizards so I can't help you there. I am also struck by the fact that I have no clear idea what precisely you mean by 'intro and outro' -- the latter in particular...!
However, if the mpegs are ready to burn to disc, and that is all you want to do, then ignore the Wizards. Instead, open the main editing program. However, do no more than select Share, then Create Disc > DVD. The burning module will then open with an empty timeline. You add media by selecting the, well, ADD MEDIA button up top. Here (I imagine) you would insert first your Intro (I assume it is a video clip of some kind).
Just above and to the left of the burning timeline, you will see a check box, and for you it contains (I think!) the magic words 'Use first clip as introductory video' i.e. what I take to be your intro. Then you insert all your other clips in the order you want ending, I imagine, with your "outro" (

). You can, on the next page, then select your menu templates (if you want them). If you want no menus, then click the Edit tab on the second page, then the Advanced button and de-select the menus. Preview, then burn. Voilà!!!