Titanfall2folder can vary depending on whether you purchased the game off Steam or Origin, and if you set a custom folder for game installs.
C:\Program Files (x86)\Steam\steamapps\common\Titanfall2
C:\Program Files (x86)\Origin Games\Titanfall2
C:\Program Files\EA Games\Titanfall2
NorthstarLauncher.exeto start Northstar
ns_startup_args.txt, these will also be overwritten. If you want to keep the changes you made make sure to make a copy of these files beforehand and change them back after applying the update.
ns_startup_args.txt, which should be in the same folder as you extracted the Northstar files to.