As said, start at the beginning, look at the razor… before you take it apart to see how it fit in the old scales… then at the blade once you have it apart.

When the razor has the old scales on it, is a good time to experiment moving the blade from side to side or look for potential problems with the blade.

Mock-up will tell you a lot about how it will go together. Making the pin holes a bit larger will give you some wiggle room, use a hand held pin vise.