Hello Promoth,
Greetings of the day,
For your query understand one aspect that Sfin migration is a technical migration and now like a full fledged change like New GL.
So for your question below is response:-
1) In User acceptance you need to install the sfin again
2) The customizing will move as TR
3) Run the migration project to check data move to new structure and new setup
4) Confirm and perform UAT & other steps put in AC100
Regards
Rishab