Select the Insert section and then select More Gadgets.
Find and open the Insert menu in the Google Sites Editor. You should be able to see a list of available gadgets you can install on your site, including Tables, Links, and Images Find and select the More Gadgets option. This will allow you to add customizable tools like POWr Mailing List to your site.
The Gadget manager will be visible. Click on Add Gadget by URL. Then add this exact URL into the field. Click Add to finish.
Now that you've added your new, editable Mailing List Widget to your Google Sites page, you might want to resize the Widget. Using the options in the pop-up window, choose the height and width of your plugin. You can decide to create a title, scrollbar or title around your Mailing List Widget, but we advise against it. You’ll have more editing controls directly through the plugin.
Set up POWr Mailing List
Visit the live Google Sites website and select the Settings Icon in the upper right corner of the Mailing List Widget.
In the POWr Editor, click Import Existing Mailing List, find Mailing List- and click Copy.