First Adult passport-birth certificate

Hello,
I am finally applying for the first Adult British passport after receiving Citizenship certificate. I am getting confused with the supporting documents. Everywhere on the forum people refer only to the passport (of another country) they used to enter UK and citizenship certificate. However on the leaflet that comes with the passport application form they ask for a birth certificate and parents marriage certificate which is impossible for me to find. Is it essential to get them, also get them officially translated?
I was born after 1983 outside of EU
Thanks in advance

If you read the leaflet correctly, these documents do NOT apply to you. The same form is used for everyone. Follow only the requirements for those who are naturalised.

Brilliant, thank you