Carbide Create only understands vectors/paths — no text, special effects, or embedded pixel images. Open in Inkscape and view in outline mode to see what it will import.
For tracing see: https://wiki.shapeoko.com/index.php/Creating_a_rustic_letter and https://wiki.shapeoko.com/index.php/Carbide_Create_Photo_Tracing
For the actual drawing see: Let's draw an "ellipse" with new users and Let's Make a B (for anyone)