OTF Font Structure: Private Use?

  • Can anyone educate me or point me to one or more  reference(s) the OTF font structure?  For instance, I have a font (hello honey) from the DaFont.com website that I'd like to gain access and manipulate in CorelDRAW.  CorelDRAW has no problem  finding and applying the glyphs but CharMap doesn't show those "Private Use" characters.