[NTG-context] Probably a very simple question, but how do I get a page number to be centered, at the bottom and vertically in the middle whilst having my doc margins?

I have the following code that I tried editing with no success https://pastebin.com/jT58Z8uY This has no footer or header but when I add code for a header that is AI generated it outputs a wrong result l, and I tried reading documentation too but didn't really find anything helpful What I want; everything that is included in the preamble that affects the sizing and alignment, but I want a bottom centered page number that is vertically aligned (it doesn't have to be perfect but I think context can oroabbly do that? I'm a complete novice, sorry). Would greatly appreciate if someone can format this into the doc. Thank you!