Grab something simple and relax (4,2,4)
I believe the answer is:
take it easy
'relax' is the definition.
(I know that take it easy is a more specific form of relax)
'grab something simple' is the wordplay.
'grab' becomes 'take' (I've seen this in another clue).
'something' becomes 'it' (both can refer to an object).
'simple' becomes 'easy' (similar in meaning).
'take'+'it'+'easy'='TAKE IT EASY'
'and' is the link.
(Other definitions for take it easy that I've seen before include "Relax" , "to rest" , "avoid exertion" , "Avoid stress - remain calm" , "Put your feet up" .)