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

Publications are shared spaces for stories written around a common theme or topic, usually by multiple authors.

You need this to get it done:

Name (required)
The name for your publication (maximum of 140 characters including spaces.) Your publication's name also determines its unique URL.
Description (required)
A brief description of your publication (maximum of 280 characters including spaces.) This will be used in footers, search results, and other places.
Avatar (required)
Your publication avatar appears in previews of your publication content throughout Medium.
Minimum resolution: 60 x 60 pixels
Aspect ratio: 1:1
Publication Logo
This logo appears at the top of all your publication’s stories.
Height: 72 pixels
Maximum width: 600 pixels
Must have a transparent background.
Background (large header)
With large headers only, you can set a background image which will span horizontally across the page.
Minimum resolution: 1500 x 750 pixels
Aspect ratio: 2:1
Medium recommends uploading the largest image you can.
Background (medium header)
Medium headers may contain a background image.
Minimum width: 1500 pixels
Aspect ratio: 8:1
Add up to 5 tags to help people discover your publication.
Contact Information
You can add a publicly listed email address and Twitter and Facebook profiles for your publication.
Colour Hex Code
Set a six-digit hex colour code to use in your Medium publication (do not add the # sign.)
Requirements missing or found errors? Report

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

Medium Help Center - Create a publication
Official guide to creating a publication.
Medium Help Center - Publication headers
Official information on publication headers.
Medium Help Center - Publication sections
Official information on publication sections.
Medium Help Center - Publication images
Official information on publication images.
Link missing here or found errors? Improve How-Tos