Catechism for conversion showing basic details (9)
I believe the answer is:
schematic
'basic details' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'catechism for conversion' is the wordplay.
'for conversion' indicates an anagram (I've seen this in other clues).
'catechism' with letters rearranged gives 'SCHEMATIC'.
'showing' is the link.
Can you help me to learn more?
(Other definitions for schematic that I've seen before include "Symbolic diagram" , "Represented in simplified form" , "Represented by a diagram" , "In the form of a diagram or chart" , "Catechism (anag) - of a diagram" .)