I've got a list A. When an item is created, a folder is created in library A.
When a file is created in one of the folders in Library A, the item (which triggered the folder) from List A must be updated.
Is that possible?
thanks in advance!
Yes, it is possible. What you need to do is create relation between library and list.
Create a column in Library A 'ItemIDOfListA'.
Create flow on List A - When item is created in List A, create folder in LibraryA and update column 'ItemIDOfListA' with item id.
Create flow on Library A -
when a file is uploaded to library, get folder in which document is uploaded, get value of ItemIDOfListA column.
Query List A using item Id and updated your list item as per your requirements.
Edit - Just tried MS Flow to update Library Column with Item Id of list item which triggered workflow. It is working fine.
Design of MS Flow