How would I do this with a power automate flow?
When the column "statut" is changed to "Approuvé", take the number from the column "Quantité Approuvé" from the list "Demandes de sortie d'articles" that was calculated after the status was changed to "Approuvé". Go into the list "Liste d’inventaire Studio" in the column "Quantité Sortie" and add the number you got from the list "Demandes de sortie d'articles" in the column "Quantité Approuvé"?
These are the two lists at hand:
This is what I have created as a flow so far, but I could not get it to work.
Maybe there is a better way to go about it, as I would want it to trigger after this approval flow approves a demand:

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