Bachelor, a desolate one sadly, gets to have nothing to do (2,2,1,5,3)

I believe the answer is:

be at a loose end

I'm a little stuck... Click here to teach me more about this clue!

'to have nothing to do' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'bachelor a desolate one sadly' is the wordplay.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'sadly' is an anagram indicator.
'a'+'desolate'+'one'='adesolateone'
'adesolateone' with letters rearranged gives 'eatalooseend'.
'b'+'eatalooseend'='BE AT A LOOSE END'

'gets' is the link.

Can you help me to learn more?

(Another definition for be at a loose end that I've seen is " Idle".)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app