Step How To :: Step-by-Step

1.1 Either Log in at tumblr.com or on your tumblelog, click on the Dashboard link

3.1 Scroll down the page to Embed your tumblelog
3.2 Copy the script

This could be added to a Raw HTML page but I am adding it to a Rich Text Page. A page can be added via the menus or the toolbar.
4.1 Add a new Rich Text page: Site > Add Page > Rich Text

Delete any unwanted text on the page. Being a Rich Text page you can add any additional text as desired.
5.1 On a new line, paste the Tumblr script into the page: Edit > Paste HTML into Text

[Publish your site]

You will not initially see anything. When the site is published the last ten items will appear where the script was pasted. To see the tumblelog appear in Sandvox you need to turn on Live Feeds in Sandvox Preferences: [Step 6]

6.1 To see the Tumblelog within Sandvox: Click Sandvox > Preferences…
6.2 Below General, Tick Show "live" data feeds and pages (may slow down page loading)
6.3 Close the Preferences window.

7.1 In the Sandvox Site Outline: click on a different page and click back onto the page with the tumblelog script — the tumblelog should appear. You can turn off Live Feeds again once you’ve check they’re working.