You would put your other names on the 1st page of the voluntary petition. There is a blank that asks for any other names in the last 8 years. The "in re" space, is where you should put your current name.
If you are not going to file for a few months and start missing payments, then the creditors will begin to take action. In California, if you are only 1 day late on your car payment, they have the right to repossess the vehicle.
If you start missing credit card payments, they will turn off the credit cards (which you should no longer be using anyway) and they may attempt to sue you.
You stated that your ex is supposed to be paying child support. Is there a court order for this? If so, you should request an income withholding Order signed by the judge so that the state can start garnishing his wages.
If you were not properly served with the child support action, then you should file a motion to set aside the judgment and have it re-heard before the judge using your current income and expense information.