It actually makes no sense as a bang. Its like saying, the grenade exploded and all the shrapnel made a car. The universe would be a hollow sphere if it were a bang. If the initial mass banged all the mass would just keep traveling in the same direction away from the location of the bang with the momentum the mass received from the bang. It has to be a decay or something else that can control the masses momentum. Decaying just like stars do, then the decayed mass/energy (gas, dust, plasma, light, etc..) starts to condense via gravity into other stars/planets/BH's, depending on the quantity, type, momentum, mass/gravity, etc... of decayed mass is what gets created in the region. Momentum/gravitational attracted based collisions can also occur. Maybe all the mass/energy in the universe is orbiting the initial coordinate point. We dont notice it because everything we see is in synchronised motion.