Like most get confused when applying the British Citizenship of a child I am also among one of them

Question 1 : Which application form to fill and submit for a child for his British Citizenship application?
Scenario: Dad (having ILR) is also applying for Naturalisation at the same time using online form (https://visas-immigration.service.gov.u ... onality-an). Should the Dan add the child applicant at the same time when filling up his online form (AN) or a separate form and application would be created and submitted?
Further details are as below.
Age: 12 years
Current residency status: ILR
ILR granted year: 2020
Total Stay in UK: - 9 years
Absence from UK: ~35 days
Child born Outside UK: YES
Current Nationality/Citizenship: INDIAN
Parents residency status: ILR
Parents ILR granted year: 2020
Parents stay in UK: - 9 years
Parents Absence from UK: ~35 days
Parent born Outside UK: YES
Parents Nationality/Citizenship: INDIAN
Parents marital status: Married
Question 2: Having the scenario above: is it necessary to have one of the parents to apply for his naturalization to get the child British Citizenship?