There are several episodes in this series ‘Syria At War’. I recommend all of them.
I consider Frontline to be one of the most credible sources out there. For the past few decades I have counted on them for factual reports of events around the world. I trust PBS, always have. One doesn’t need to do much more than consider Frontlines sources and to consider who they interview and where they get their stories from.
For a comprehensive understanding of what is going on in Syria, who is Assad and what is his regime capable of , what ISIS has to do with it and where they came from as well as how they rose to power. An in depth understanding of how Obama and his administration played a part in the war in Syria and the rise of ISIS as well as an inside look at Putin’s Russia, a factor that has yet to reveal it’s influence.
I recommend starting with Obama’s War and the Inside Assad’s Regime.