To a royal order; in the finish laid to rest (8)
I believe the answer is:
entombed
'laid to rest' is the definition.
('entomb' can be a synonym of 'lay to rest')
'to a royal order in the finish' is the wordplay.
'a royal order' becomes 'mbe' (I can't explain this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'the finish' becomes 'end' (I've seen this in other clues).
'to'+'mbe'='tombe'
'tombe' inserted inside 'end' is 'ENTOMBED'.
Can you help me to learn more?
(Other definitions for entombed that I've seen before include "in a grave situation" , "Placed in a burial chamber" .)