The Esp file goes into Fallout 4/Data folder
With the esp file enabled in Fallout 4
You need to use the console to rename a certain NPC
First find the ID of the name you want to use
In console the command is -
help emma 4 MESG
use the refID in the center of the line in brackets and before'Emma' with the NPC or settler to rename selected
Ie. 
setactorfullname 13000802
When the line returned from the help is MESG: (13000802) 'Emma'