How to read how one-two generally proceeds (4,4,2,5)

I believe the answer is:

from left to right

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'generally proceeds' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'how to read how one-two' is the wordplay.
I cannot really see how this works, but
'to' is within the answer.
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

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I've seen this clue in The Guardian.

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