Action Details
Requirements and how-to articles for Tumblr's action:

Requirements
You need this to get it done:

Email Address
The email address you wish you be associated with your Tumblr account. This is where your verification email will be sent.
Blog Title and URL
Email address, password and a unique username. Usernames are in all lower-case and can only contain letters, numbers and dashes (no spaces.)
Username
Usernames are in all lower-case and can only contain letters, numbers and dashes (no spaces) (maximum of 32 characters.)
Choose theme
Choose one of Tumblr's available themes and once you've found one you like, install it on your blog.
Requirements missing or found errors? Report

How-To Articles
A list of useful links for you:

0
Official
0
Tumblr Help Center - Theme Basics
Basic information on what themes are and how to install/edit them.
Official
Link missing here or found errors? Improve How-Tos