Edward I, Wales, Scotland and Ireland
There is a useful YouTube video on Edward I (in 3 parts) starting withthe Civil Wars of the 1260s and Simon de Montfort (about 7 mins)
The second part dealing with Edward I’s conquest of Waleshere (about 7 mins).
The third part dealing with the wars with Scotlandhere(about 7 mins)
Edward II and III
Another useful video from the same source on Edward II can be found here.
And Edward III here.
Richard II and disputed succession
The origins of the wars of the Roses lay in the death of the Black Knight and the reign of Richard II.