I presume that by "Vintage disc" you mean that you bought the Vintage StylesPack from Photodex.
If so, all you need to do is to apply the styles supplied in that pack. (after installing them first, of course
)
But just to clarify this a little further: Applying a style means that all the contents of your slide will have the motion effects, the adjustment effects, and the backgrounds that come with those styles. So, if you have colorized your images in sepia, using ProShow, that colorization will be lost once you apply the style. You will need to colorize again, after applying the styles.
I don't know what you bought from Digital Hotcakes. If you bought video clips, then you need to place them in your slides. You can use them as backgrounds in your slides. Just make sure that they are placed at the bottom of your layers stack (the last layer), so that all the other layers may be seen on top.
If you bought something else, better ask them how to use them in ProShow Gold.