Select the Insert menu then click More Gadgets.
Open up the Insert menu in the Google Sites Editor You will be able to see a list of gadgets you can add to your site, like Links, Tables, and Images. Select More Gadgets. This will let you add editable tools like POWr Slideshow to your site.
Copy and Paste URL
You will see the Gadget manager. Click Add Gadget by URL. Copy and paste this URL into the box. Click on Add to finish.
After you add your new Slideshow Widget to your page, you're probably going to want to adjust the shape and size of your Widget. Use the different options in the window to select the height and width of your plugin. We don't recommend it, but you can insert a scrollbar, title or border to your Slideshow Widget. There is more editing control through the plugin itself.
Set up POWr Slideshow
Visit your live Google Sites web page and click the settings gear in the upper right corner of your Slideshow Widget.
In the POWr Editor, click Import Existing Slideshow, find Slideshow- and click Copy.