Initially, Don follows condition as explicitly set forth (6)
I believe the answer is:
stated
'set forth' is the definition.
'stated' can be an answer for 'set' (thesaurus). I'm not sure about the 'forth' bit.
'initially don follows condition as explicitly' is the wordplay.
I cannot really understand how this works, but
'condition' could be 'state' (the state something is in) and 'state' is found in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for stated that I've seen before include "Expressed, detailed" , "Declared or asserted" , "Asserted, affirmed" , "Expressed in written or spoken words" , "Expressed in speech or writing" .)