i was wanting to know how to overlay letters to be able to make one color and then overlay it with another color when cutting it out for a vinyl plotter

I'm not terribly familiar with the cutter/plotters, so I would need more info before I can offer suggestions.

When you overlay the letters, do you want to cut out one color, or the other color? Or the intersection of the colors? Or difference, union, etc? These are called Path Operations, accessed in the Path menu.

But I'm not sure. It also sounds like you might be looking for Clipping. Can you tell me, after you overlay the letters or colors, what do you want to do next?

(PS - I'm moving you topic to Inkscape and Cutters forum, where it might attract support from those who are more familiar with this process.)

if you looking to have one color larger than another and layer them centered on top of one another -

highlight the letters you want to cut - then copy and past them to another area on the page (now you should havde 2 copies of what you want to layer )

then highlight the first one -- then i believe hit shift-) that will make it larger you may have to do it a few times -

then cut them out of the colors you want - then layer them no problem