In the Tumblr Editor, open your Account Settings and select Edit Appearance.
On the next page, select Edit Theme.
Click on the Edit HTML link.
Paste this exact script into your Tumblr HTML file. It's best to add it between the Head tags. Then update and save.
Create Text Post
Return to your Tumblr Admin page, and create a new Text post.
Paste this shortcode into the post and save. You'll see the new POWr About Us plugin when you expand the post. You can edit POWr About Us by clicking the POWr Settings Icon in the corner.
Edit your About Us on Tumblr:
Go to the live Tumblr web page and click the gear icon in the upper right corner of the About Us Plugin.