To activate any of the assign options, you must first click on the face of one (and only one) of the profile parts. selecting the particular assign option will link that profile part to the option selected.
In the example below, we have clicked on the face of the outside Profile. The Assign Options (shown in the Profiles toolbar) are now active and can be pressed. We will click on the Assign Outside Profile (Toolbar icon "O") to link this graphic with the outside profile.
if you deselect the face (by clicking outside the face), notice that the toolbar options only have the Outside Profile active. This confirms that there is a graphic linked to the Outside Profile.
Pressing the Outside Profile Button now will release the graphic from this assignment and the button will now be greyed out.
After linking all of your graphics to their respective parts, you can now save your profile.