If all you are trying to do is to respond to the summons and complaint within the 30 days, in order to prevent the creditor from getting a default judgment against you, then the fastest way is to go to the same website you reference and look for "Judicial Council Forms". The form you would want is called "Answer - Contract" and is form number PLD-C-010.
HOWEVER, this type of answer may not be appropriate in your particular case or may not be the best response for you to this particular complaint. There are many other proper responses available to you when responding to a summons and complaint. An Answer (as discussed above) is only one of them.
Other options are a General Denial (form # PLD-050), which is shorter and easier to fill out than the above-referenced "Answer" form, or you might want to challenge the correctness of the service of the summons on you by filing a Motion to Quash. Also, if the facts of your case warrant, you could file a Demurrer to the Complaint, or a Motion to Strike. Those are both "long-form" pleadings (not Judicial Council forms) that are methods of response that are proper and may protect your rights to object to the format or contents of the complaint (for example a Demurrer tests the legal sufficiency of the Complaint that you were served with).
For all these reasons, you should seek the advice of a local attorney, or legal self-help clinic, to advise you on whether a basic Answer or General Denial is sufficient, or if there is any reason why you may want to respond with an attorney-drafted challenge to the legal sufficiency of the Complaint through a differnent type of response. Note that the General Denial form cannot be used if the Complaint is "verified", meaning the Plaintiff, or a representative of the Plaintiff, has signed and attached a form called a "Verification" or has otherwise stated that the information in the Complaint is true and correct.