Choose Insert, and then More Gadgets.
In the Google Sites Editor, find the Insert menu, and open it. You should be able to see a list of available gadgets you can install on your site, including Tables, Links, and Images Click on the More Gadgets option. This will allow you to add customizable tools like POWr Subscription Payment to your site.
Copy and Paste
The Gadget manager will appear. Click on Add Gadget by URL. Copy and paste this URL into the box. Click Add to finish.
Adjust Height and Width
Now that you’ve added your new, customizable Subscription Payment Widget to your Google Sites page, you’ll probably want to adjust the size and shape of the Widget. Using the options in the pop-up window, choose the height and width of your plugin. If you'd like, you can add a border, title or scrollbar to your Subscription Payment Widget, but we don't advise it. You’ll have more editing controls directly through the plugin.
Set up POWr Subscription Payment
Go to the live Google Sites website and select the gear icon in the top right corner of your Subscription Payment Widget.
In the POWr Editor, click Import Existing Subscription Payment, find Subscription Payment- and click Copy.