Hover the gray "Databases" tab above to see the list of databases. These are listed by alphabetical order. Each one has its own help page. Use your mouse scrolling wheel to go down in the list. Click a database name to see the help content.
Within the database help page, the logo links to the database. Below the logo are videos or other media to help you navigate your way in the selected database (or platform) and learn all of the available features.