Our story follows from Episode 7 and the new canon growing from it, although we generally hope to include most older EU material as best we can - we're fans, after all.
After the Empire's defeat at Jakku, the Galactic Concordance enforced their surrender and established the New Republic. But memories of bloated bureaucracy and autocratic tyranny alike resulted far weaker and less centralized government, one that soon scaled back its fleets and promoted a peaceful vision for the galaxy. At the same time, the Imperial remnant gathered in the Unknown Regions, building shipyards, stations, and superweapons in near total secrecy. Living and training exclusively on their new generation of advanced warships, eschewing territorial expansion for mobility, technological advantage, and the element of surprise, the First Order prepared to strike. Those preparations came to fruition when they unleashed their newest weapon, destroying the Hosnian system and murdering much of the senate.
Only General Leia Organa's intuition averted total defeat: with tacit, unofficial Republic support, she had organized the Resistance to combat the threat she knew would come, treaties-be-damned. Their counterattack against Starkiller Base left both sides crippled, and engaged in a bloody, covert war across the galaxy, even as the Republic scrambled to reconstitute its leadership. Many systems feared or resented becoming embroiled in a new conflict, once again driven by the human-dominated core. A number of systems formed the Unaligned League, pledging themselves to non-involvement, self-governance, and mutual defense. Other galactic powers began asserting themselves as well; the Hutts feel it is time to reclaim an Empire that once spanned from Tattooine to the Tion Cluster, while the Corporate Sector (sucessors to the Separatists of the Clone Wars) plays all sides against the middle for their own profit.
While the Resistance battles the First Order on largely even terms, and political schemes play out on the galactic scale, the Jedi struggle for daily survival. The Knights of Ren slaughtered most of Master Skywalker's initial disciples and destroyed his temple, although a small handful of senior students managed to escape. The Church of the Force, which safeguarded sensitive children and exile Jedi during the dark times, provides a support network to these refugees, who teach Skywalker's lessons as best they can with their own limited training. Yet with Kylo Ren's destruction of the Church on Jakku, these followers of the light know they are only steps ahead of their foes.
Without The Jedi, There Can Be No Balance In The Force.