The "545" holder (top item in the image) uses single-sheet 4x5 Polaroid film, and slips into the back of your Graphic just like a conventional film holder. FWIW, it looks like the one you got is actually a 545i, and made of plastic. The plain 545 is an earlier model and made of metal. The 545i (and the new 545pro) can also be used with both Kodak Readyload and Fuji Quickload single-sheet films. Some of the earlier metal 545s have problems with the Kodak and Fuji film sleeves.
The lower holder may be a back that uses pack film, somewhat smaller than the single-sheet 4x5 Polaroid, and may attach via a Graklok interface. Your Crown may or may not be Graklok equipped. If you have little slider bars that hold the back on the camera, that's the Graklok part. No slider bars, no Graklok.