Hi there,
The linking process allows you to take the DTM Production embed code, with its matching host location, and use that same embed code with your Launch production environment.
The linked embed code will load one of two things:
1) The DTM Production library
-or-
2) The Launch Production library
whichever is most recently published.
When we link one DTM embed code to Launch, and publish it to production, the Launch or DTM code will work for that website as per the existing rules/data elements et cetera where the latest published library(DTM or Launch) will take into effect.
https://docs.adobe.com/content/help/en/launch/using/reference/upgrade/link-dtm-embed-code.html
Hope this helps!