The Redmine home page, also accessible from the first link at the top right of the default Redmine theme, can be customized from inside the system. It can contain links to Redmine tutorials, YouTube videos, your company page, or any kind of Textile/Markdown formatted content.
Make sure that you have Redmine administrator permissions.
Navigate to Administration | Settings | General Tab and edit Welcome text:
Any content entered here will be displayed on the Home page, or when the Home link is clicked. After you enter or edit content, click Save at the bottom of the form, and click the ...