Simple expression to update a column based on last log entry

Hi !

I’m a new Appsheetp user and I am building a simple Inventory Management App with two table : Product and Inventory Logs.

I would like to create a simple expression to update Available quantity of my products based on last Qty entry logs. It should consider the following :

  • Last DateTime
  • Key reference
  • Update quanity (I don’t want SUM function, I jst want to update the related column…)

Can you please help me ? Thank you !