That’s okay, there are some great tutorials for how to get started in Inkscape here, and quite a few folks who know how to use it really well. (I’m not one of them, but I can probably get you started with a tutorial that tells you how to do what you are trying to do.)
This one discusses how to do a complex trace in Inkscape. If yours is a simple raster image, it should be easy to do using this method.
If your file is already a vector engrave, all you would need to do is copy the outermost path line in the same place, change the color of the copy, and give it no fill. That will become a vector cutting path. The general rule is Fills get engraved. Stroked paths with no fill become cut or score lines. So if you create a second copy of the outside path, and give it a different color stroke, you’re creating a cutting line.