The war between the First Order and the Resistance began upon the escalation of the cold war into full-scale open warfare between the two factions for control over the galaxy.

While the first order, the successor to the fallen Galactic Empire, sought to conquer the known galaxy from the unknown regions, the resistance sought to preserve the democracy restored by the shattered New Republic after their struggle against the Empire thirty years prior. 

“The war is just beginning.“ – Jedi Master Luke Skywalker