When I open an svg file it comes up as an outline as expected, but when I try to add another svg file it deletes the first, how can I add my second without the first going away?
I’m afraid Carbide Create isn’t able to open up multiple things in a single file — to do so, use Inkscape to open multiple files and copy-paste them into a single file and open that.
EDIT: Note that since the above was written Carbide Create has gained an “Import External File” option which allows importing additional elements as DXF or SVG files.
Please note that Carbide Create will only handle simple path objects — it won’t import text or anything else. Please see: http://www.shapeoko.com/wiki/index.php/Inkscape#Converting_Text_to_Objects