I do not have information on ‘46 but here are the directions for AD plates, these come with the NOS plates and I have not seen them in the accessory manuals.
https://www.flickr.com/photos/advance-design_parts_co/12616625763/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/41439937240/in/album-72157631868452754/
On my truck I use the ones the vendors sell, I placed them by modeling where I planted my foot getting in and out.
https://www.flickr.com/photos/advance-design_parts_co/35467524043/in/album-72157631867396207/