Yes, so you can respond and act pro se.
You can represent yourself and would need to answer to the papers they filed and dispute or contest this. You should be able to file on your own, but I would just speak with the clerk and see if any local rules require you to file anything other than your pleadings stating it.
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The County of San Diego has filed the child support papers. I want to represent myself. How do I file paperwork for myself? Will I need to file other papers to establish that I am the plaintiff?

I understand that you want to represent yourself in the child support case. Have you already received the child support papers from the County of San Diego?

Yes. I am the other parent. The non-custodial parent is the father.

Are you looking for guidance on how to file the necessary paperwork to establish yourself as the plaintiff in this case?

Yes.

Is there anything else the family lawyer should know before I connect you? Rest assured, they'll be able to help with establishing yourself as the plaintiff.

No

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Yes, so you can respond and act pro se.
You can represent yourself and would need to answer to the papers they filed and dispute or contest this. You should be able to file on your own, but I would just speak with the clerk and see if any local rules require you to file anything other than your pleadings stating it.

Please let me know if there is anything else I can answer related to this, or if this has answered your question fully. I hope that this information is helpful to you.