Need help for a workflow linking automatically a record in a related entity

[Maximus]

Hello,
you need to uncheck the 'Silent Mode' parameter on the Import step one to allow trigger workflow upon import https://docs.espocrm.com/administration/import/.

[Flof]

hello everyone,

i think that the clue is probably in front of my eyes, but i can't find may way !
so i need your help !
here is the situation :

i have 2 entities : entityA and entityB. entity A has a many-to-one relationship to entityB

both entities have got field named : CodeNumber

all the records of entityB have been created in espo.
a regular import will create the entityA records everyday.

what i would like is : whenever a entityA record is created, i need to have it linked to an existing entityB record, where CodeNumber(entityB) = CodeNumber(entityA).

this codeNumber field is neither the name, nor the Id of the record, but just an additional field.

i tried so many things with formulas and so on in the workflow (after record is created) but nothing worked.

if anyone knows the correct method, that would save my last hair on head !