"Older posts" missing…

what theme are you using?

Twenty twelve.

If you are using Twenty Twelve unedited, then just upload a fresh copy of this theme.

I’ve edited it significantly…

I’ve edited it significantly…

To protect your work, hope you have craeted a Child Theme!

piece of navigation was missing – the “older posts” navigation at the bottom of my pages

Probably that part of the navigation got deleted in one of the theme’s templates.

First, try checking single.php

Okay, but what code am I specifically looking for?

navgation

Okay can someone else give me a hand who doesn’t give the most general, one-word answers possible? I mean thanks for trying but jesus.