Welcome,
Congrats on your new Brunswick treadle. This manual from "The Needlebar" should help out on some of the basics, just skip the motor parts:
http://needlebar.org/main/manuals/re...ay/1index.html
National parts aren't as easy as Singer to get a hold of but not difficult either. The Brunswick needles go by various names depending on the brand such as Eldredge FS (Flat Shank), 20x1, Boye 14, BB, 712, etc. The needle itself measures about 1-3/4" with a 2mm shank which is flat on one side. A commonly found replacement shuttle and bobbins would be Boye 13---though sometimes the wrong parts get mixed in with the right wood tube or clip. Good to know bobbin and shuttle dimensions and appearance to double check before buying anything.
Please post a pic of your new treasure if able. Everyone loves a photo. Good Luck and Enjoy.
Jon aka jlhmnj