First of all, check the obvious: look for infinity stops or notches, and check to see that you have the proper cam installed.
Did it come with a ground glass back? Without infinity stops or a distance scale, you would need to use that to locate the standard at infinity. Once you have found infinity once, you just need to mark it. My Technika, a version III, uses hand-filed notches on the bed rails to mark infinity. I am not sure if later models used separate mechanical infinity stops or used this same method. If you do not have a ground glass back, you could stretch a piece of wax paper tightly across the film gate in the roll film back, mount the back without the insert, and find infinity on the wax paper. Then, mark the location of your front standard with a Sharpie marker. Obviously not ideal, but it will get you closer than you are now.