Citizenship help

[mk21600]

So after living in the UK since 2001 on the ancestral Visa which has being upgraded to indefinite leave to remain for the past 14 years.
I’ve recently applied for British citizenship but all I’ve done is paid the fee on the website and downloaded any forms I need to take him along with character references.
I need to do my biometrics but I’m not sure whether this can be done out of normal post office or does it have to be at one of the centres, as I’ve checked and there are no appointments for the next two weeks at all only the ones at the premium Centre in London which cost £260.

I also have a few other questions namely what all do I have to take in as I’ve read that people have had a scan in documents but there was no mention of me scanning in any documents on the application I assume that I just take my passport wrong with my wife’s passport and marriage certificate to the centre if I choose to use it or what happens if I go to post office route getting my biometrics.

I also have a few other questions namely what all do I have to take in as I’ve read that people have had to scanning documents but there was no mention of me scanning any documents on the application I assume that I just take my passport wrong with my wife’s passport and marriage certificate to the centre if I choose to use it or what happens if I go to the post office route getting my biometrics.

Many thanks