Here’s a link to the section of Linked in that explains how to select the widget button you want to add to your blog. Click on the Promote Profile link on the page that this link sends you to.

The widget allows your readers to jump into your Linkedin profile in case they want to network with you more directly beyond commenting on your blog posts. You have your choice of a few different button styles so see what you like, copy and paste the script into your site, and see how it fares for you.