Depending on where you installed all this you load one Horn at a time from Poser Formats > Figures > Daz Characters > V4 Creature Creator > Universal Horn V4.CR2 whilst V4 is selected.
Then Select each Horn and go to Poser Formats > Poses > Daz’s Victoria 4 > Add-Ons > Creature Creator > And choose which shape and position preset that you want.
Oh and as for the head shapes…the icon that show what the shape is does not mean it shapes V4 to the shape. You have to go to the Parameters Pane whilst V4 is selected and use the adjustment setting to make her head that desired shape. Most Morph injection icons work this way but not all.