Confluence Data Center-How to add the third node?

Dayu

I've installed confluence data center on first node and second node. I can log in with admin user and find cluster information. There are two nodes display and I think it's nothing wrong.However, when I add third node, according to the course https://confluence.atlassian.com/doc/installing-confluence-data-center-203603.html. I found that there is not the third node display on clustering information.
Why is it?
By the way, the license I used is an evaluation license.