You can launch Northstar via Steam, Origin, or EA using launch options.
If Northstar doesn't appear to be installed, or you have issues entering the lobby, try running vanilla files. It's hard to say what VPK mods could cause issues with Northstar at the moment, so it'd probably be easiest just to try running unmodded.
Northstar can also be launched through Steam or Origin using the "add a game" feature. This allows you to register any .exe as a game. To set up Northstar, navigate to your Titanfall 2 folder and choose NorthstarLaucher.exe.
steamaddgame
originaddgame
Adding Alternate Launch Option for Steam
Steam can be configured to prompt for starting either Northstar or vanilla when Titanfall 2 is launched. This example uses SteamEdit, however another appinfo.vdf/packageinfo.vdf editor can be used.
Download SteamEdit, extract it, and run SteamEdit.exe. Select Titanfall® 2 from the dropdown.
steameditselecttitanfall2
Click on Edit Launch.
steamediteditlaunch
Click on Add New.
steameditaddnew
Enter a name for Northstar and enter NorthstarLauncher.exe as the executable.
steameditlauncheditor
Click OK to close LaunchEditor, and click Save & Refresh to save your new configuration and restart Steam.
steameditsaveandrefresh
Launching Titanfall 2 will now display a prompt for vanilla and Northstar.
