The Normals command draws 3D Lines with normal (perpendicular) vectors of selected 3D Faces. On the prompt Draw Normals or recolor Faces?

[/Faces]: you can choose to either draw unit normals (from the 3DFACE center outwards), or recolor the selected faces to blue or red. Any normals going away from you indicate a backface. Normals are drawn in the layer "NORMALS" and have a length of 1/20 of the size of the current viewport. Red normals or faces go (face) towards the current viewpoint (camera), blue normals go away from the camera (eye).

The color depends on the current view - if you change your 3D view, rerun the command. With the Faces option and in shaded views, you should only see red faces (blue ones are backfaces). Any missing "fur" and blue faces indicate a problem of backfaces on your model - these faces e.g. may not be rendered properly (when a single-sided material is used). You can use FLIPFACE on such 3Dfaces.

The installer that ran when you downloaded this plug-in from Autodesk Exchange Store has already installed the plug-in. You may need to restart Autodesk Product to activate the plug-in. To uninstall this plug-in, click Control Panel > Programs > Programs and Features (Windows 7/8.1/10/11) or Control Panel > Add or Remove Programs (Windows XP), and uninstall as you would any other application from your system.