Tell Plone about your new skin folder
The next step should be to make sure your skin folder appears in the portal_skins listing, so see the example screen below:

a_first_skin is clearly visible in the alphabetical listing. Now click on the Properties tab at the top of the screen.
This will being up the following portal skins properties screen:

The first thing to notice in is that there are two skins already on your system called Plone Default and Plone Tableless. These come with your Plone installation. It is the Plone Default skin that creates the familiar light blue site with the Plone logo, etc.
If you look toward the bottom, you can see that the Plone Default skin is currently the Default Skin for the site. We will change that soon.
For now, go to the Add a new skin section and type in the name of your skin a_first_skin into the Name field. Click the Add button.
Hello, I am Jamie Robe, author of the 
