If a civil war begins, it will because we, the straight white men, begin it, the jewish regime has no interest in risking it's power by triggering an armed conflict, they want things to go smoothly and quietly, so every effort is taken by them to ensure fighting will not break out, they know that hiding behind goyim makes rebellion difficult because we are less willing to harm those we consider to be undeserving (rightfully or not).
We will gather into groups, head towards the wealthiest areas of the nearest cities, and lay siege to the people who live there (jews and their puppets).
We will then fight with the security and police, and shift to declaring war on the police themselves, who are the first line of defense and frontline troops for any regime, anyone in a police uniform is wearing the uniform of the enemy, and we must wake up to the fact that if the war is going to happen, we will have to begin by killing the cops or taking them prisoner.
After that, we can expect the national guard to show up just as before, the jews will force us to butcher our fellow gentiles to liberate our countries, an at that point we must do so without hesitation.
When enforcement for the enemy regime is removed, that land becomes our own, there may be local resistance from civilians, but we could likely put them down easily if we were strong enough to take on the cops and national guard and win.
We immediately begin to set about rebuilding what was torn down, we show the people what our idea of an alternative to the government we fight against would be like, new government, new laws, new everything, order must be enforced, and it must not be totalitarian, in fact, it should be more lenient than the way things were done under the previous regime, because the place must appeal to the people who are there, or they will leave or turn against us.
First thing is to set up housing and feeding them, as well as providing them with everything they need, we will have to do this because the regime will cut the area off from all the things it depends upon from the outside, so the place will need to become entirely self-reliant or it will fall on it's face in short time.
We will need to set up defenses and fortifications, in order to keep the regime out and keep the people in, many people will want to escape, even after we have set things up to make them want to stay as much as we could, we cannot allow them to leave, because of the risk of them leaking out information to the regime or otherwise betraying our rebellion to them, contact with the outside must also be silenced.
Once our territory is well established, and we have endured and repelled the attacks of regime forces seeking to reclaim it, we can move out to expand our land holdings, claiming more territory, then taking the time to develop it into something sustainable and defensible, and moving on.
A good approach is to try and win the hearts and minds of the people in the lands we claim, to make them prefer us to the regime, despite us having less to offer, to that end we should focus on giving them a government that provides them with the things that the regime did not, things that they would greatly prefer not to lose, ideas include providing more freedom, there will be lots of laws and rules that could be cut down, which I guarantee would immediately make a lot of people a lot happier with you, more opportunity, especially economic or educational, better treatment, more personal and reasonable governance, especially when it comes to the law enforcement and justice systems, etc.