If you've already set up an account on Repost.Us, getting your Tumblr site set up is quick and easy.  Just follow these steps:

Step 1: Sign into your Tumblr Dashboard

Step 2: Click on the "Preferences" Gear

Step 3: Click the "Customize your blog" button

Step 4: Click "Edit HTML" on your theme

Step 5: Paste the javascript snippet containing your API key under the <!--DEFAULT VARIABLES --> area in the HTML

(Note: You can find this code snippet on Repost.Us. Simply log into your account and in the Repost.Us Installation of your Site Summary it is the second code snippet. This tutorial is done with the free Redux template, some templates may vary on placement)

Step 6: In your Tumblr template's HTML, locate the "block:text" (you can do this easily by simultaneously holding down the Ctrl and F keys on Windows or the Cmd and F keys on Mac) and paste the button code located on the Repost.Us installation page (the first box in the previous screenshot).

 Step 7: Save your results, and you're done! (Click Update Preview >> Appearance >> Save)

If you have any additional questions about how to get Repost.Us working on Tumblr, please feel free to contact us!