Go to your Account Settings and click Edit Appearance. Then click Edit Theme.
Underneath Custom Theme, click Edit HTML.
Copy and Paste Script
Paste the POWr script into the HTML file between the Head tags. Then update and save.
New Text Post
Back inside the Tumblr editor, add a new Text Element.
Copy and Paste Shortcode
Paste the POWr shortcode into the text post, then save You'll see the new POWr Staging Dev plugin when you expand the post. Click the POWr Settings Icon to set up POWr Staging Dev.
To edit your Staging Dev on Tumblr:
Visit the live Tumblr website and click the gear icon in the top right corner of your Staging Dev Plugin.