Sales & Marketing Source has a very comprehensive set of help pages. Click 'Help' under 'Research Tools' in the left-hand 'column' below My Dashboard.
That will open the EBSCO help homepage.
The help pages are not specific to Sales & Marketing Source, as all other EBSCO research databases work in the same way. So don't expect to find anything specific to Sales & Marketing Source. That said, the pages are extremely detailed.
Click on the magnifying glass on the top right of the page to open a search box if you wish to search for a specific topic.
EBSCO offers regular webinars on using their products. The calendar is available here. Note that EBSCO offer a wide variety of products, hence relevant webinars may take a while to come around.
EBSCOhost Research Database Tutorials
EBSCO Information Services YouTube Channel
EBSCO Tutorials YouTube Channel