Hello,

You can go through the digital marketing course offered by Google, it's free of charge, there are a total of 26 modules, you'll be provided all the  information, and at the end you need to qualify the test,  you can also watch some very good channels in Youtube which provide a detailed information regarding digital marketing such as edureka, Simplilearn etc which are also for a pretty long duration, in case you cannot continue for such long hours, there are also chunks for each topic which you can watch out in case the longer duration isn't possible.