The dashboard is the default loading page for your Confluence site. This page can give users all the necessary tools to find other pages, re-enter unfinished work or quickly navigate to favorite spaces and pages
Your site's welcome message will be on the right side of the Confluence site's page, and this is the best place to introduce your site to users.
Check out the Editing the Site Welcome Message page to find out how to add notifications, useful links, images, macros and other information.
You need to have Confluence administrator privileges to edit the site's welcome message.
https://www.cwiki.us/display/CONFLUENCEWIKI/Customizing+the+Confluence+Dashboard