Chaenomeles

Subject line explains it. Looking for someone to help me. I have the curious ringtail avatar and I have a mod for that specific avatar. I need to change the head texture of the ringtail to the texture of the mod. The mod's directions say to "drag the texture from my inventory onto the head prims" I've tried dragging the texture onto my avatar's head. I've tried editing the head then trying to change texture in that menu. Can I actually change the texture with a "no transfer" texture? Why is this not working? Thank you for anyone who can help.