Adding:

• Some information mentioned by @maxandersen in the [Transaction gdoc draft](https://docs.google.com/document/d/1jLNPsgC57V3S1FjWpbWJJcRB13-MSi_WmVneABOitMc/edit#heading=h.sfkagbodhz8p).
• Link to a complete list of Narayana configuration options.
• Additional context info and proper terminology.
• Removing metadata `:sumary:` from the top of the file since this is automatically taken from the first sentence that acts as guide intro.
• Adding metadata `diataxis-template`: reference
• Tiny style tweaks.
• Proper headings capitalization

@zhfeng @mmusgrov , please have a look and provide an SME review when time and mood.
Thank you.