Right click on your desktop shortcut, which points to FP, select properties. The shortcut should finish Pinball exe", simply add to this a space after the " followed by
/Arcaderender
EG "C:\Program Files\Future Pinball\Future Pinball.exe" /Arcaderender
When you now run the shortcut you should now have an option to select the arcade camera in settings, then follow the guide to resize playfield, and backglass using Scroll lock keys.
Cheers Buzz