How to make bats sell out? (8)

I believe the answer is:

backstab

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

'sell out?' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'how to make bats' is the wordplay.
'how' becomes 'back' (I can't justify this - if you can you should believe this answer much more).
'to make' indicates anagramming the letters.
'bats' with letters rearranged gives 'stab'.
'back'+'stab'='BACKSTAB'

Can you help me to learn more?

I've seen this clue in The Independent.

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