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

paid action
Text Ads are simple ads served on the right-hand side or top of the LinkedIn desktop feed.

You need this to get it done:

Campaign Manager Account
In order to be able to use LinkedIn's Campaign Manager, you must made an account for it. You need to enter an account name (up to 100 characters including spaces), your currency (which cannot be changed later) and if you wish you can associate a LinkedIn Page with your account, but this is optional (although some ad formats require a Company or Showcase Page to be linked.)
Campaign Name
The internal name for your campaign (not visible to the public.)
The headline for your ad (maximum of 25 characters.)
The description for your ad (maximum of 75 characters.)
Choose the language of your campaign.
Landing Page URL
Decide where you want the user to go when the click on your ad (either your LinkedIn page or your external website.) Links must begin with http:// or https://.
Image (optional)
File format: .jpeg/.jpg/.png
Resolution: 100 x 100 pixels
Target Audience
Choose your target audience based on attributes such as location, job experience, interests, etc.
Decide how long you want your campaign to run. A starting date is required (either start immediately or schedule a starting date) and you can enter an end date if you wish, or leave it blank for your campaign to run until your budget runs out.
Budget and Bid Type
Choose your budget (either daily or total), bid type (cost per click vs. cost per impressions) and the bid amount.
Requirements missing or found errors? Report

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

LinkedIn Help - Creating a LinkedIn Text Ad Campaign
Official guide on creating a Text Ad campaign.
Link missing here or found errors? Improve How-Tos