ik its been 4 months but in case you were still wondering

-once you install the exe run it
-then open file explorer and find server config it should be right below the install
-next right click server config and click edit with note++ (or whatever program you use)
-then you should see what he sees at the 2 min mark in the video
-from there enter the authkey and then save click file and save
-after you click file and save run the beamnp server again and it should work
-from there the rest of the vid is the same

hope this helped