All of the Available tutorial can be found on the tutorial library page:
for each extension there is a getting started guide that will help get started with the basics for each extension.
for example, on the tutorials page, set the Filter to show extension for Data Bridge:
one of the Tutorial returned will be the Data Bridge getting started guide:
It will also return other getting started guides for the extensions that make up Data Bridge like Data Assist:
and Security Assist:
and others. You can also set the filter to return Design Extender or eCart tutorials.