If there's only two holes in the master cylinder for brake fluid, then it sounds as though it is a diagonally split system.
The master cyl may be shot or just need bleeding first, very often forgotten!!
Get a helper tp ress the brake pedal and hold down, then put your thumb over the hole in the master cyl where pipe would go keep there whilst pedal is released, now remove thumb repeat a few times, the suction caused by the returning pedal will soon get it working, it's possible the spring is broken in the master cyl, there's two, but these are cheap enough.
tabetha