Pictures: Search Google for your topic. click on Images, then tools, then select "labeled for reuse". Or use Weebly pictures or use pictures from (website that has free images)
Earn a certification in "introductory" digital marketing from Google
Digital Marketing Certification (American Marketing Association)
What if I have no clue what topic to cover?
Use this OR this come up with ideas
5 D's of digital marketing
How affiliate marketing works
Amazon affiliate percentages: how much cam you make.
Sample of Adsense or similar
Sample of other ads.....
Sample of starting point