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