First, you must have the Addon/Extension Personas for Firefox installed (and of course be using Firefox Web Browser.)  If you don't have Personas for Firefox yet you may download it from here:
[link]

Second, if your image files (Header and Footer files) came in a .zip file, you'll need to extract them into a directory of your choice.  If you don't have an extraction program, Windows users can download the free utility 7Zip here:  [link] Mac users  can download StuffIt Expander here: [link]
Remember where you put your image files.


Once Personas for Firefox is  installed, you will see a little orange fox icon at the very bottom left of your open Browser window.

1) Left click on the fox and a menu will spring up.  

2) From that menu, select "Custom" and another menu will appear.

(If you don't see the word "Custom" you may have fiddled with this before and the name of whatever Custom Persona you typed in will appear in it's place.  In this case, select that name.   In any event, it will be the menu option just below 'Category'.)

3) From this new menu that opens, select, "Edit".  

(Now a new tab or window, depending on your Browser settings, will open.)

4) Type a name for this Persona in the "Name" bar.

5) Beside the Header bar, click the "Browse" button and navigate to where you stored your  Persona image files, then click on the Header image you want and select "Open".

(The image should appear at the top of your browser.)

6) Beside the Footer bar, click  the"Browse" button, go to where you stored your Persona image files, click on the Footer image you want and select "Open".

(Make sure you select an image labeled "Header" to appear at the top and "Footer" to appear at the bottom.)

7) Select a Color for Text by clicking on the colored square and picking one from the choices that pop up.

8) Select an Accent Color the same way you chose a Text color.

9) Click, "OK".

The window or tab will now close and you should now be wearing your Custom Persona.
Enjoy!