There seems to be a bit of confusion here, technically you are asking about 2 different models
The Wrebbit published Harley kit,
or,
The 1903 Harley Davidson designed and built by AlanG
Build thread here
If you are asking about the model from AlanG, the link I provided is the best instruction set I can give you, and maybe Alan will chime in with any additional resources he might have.
If you are asking about the Wrebbit kit, you might be able to find the instruction booklet on the internet, somewhere.