Once the parts are gathered, you have to trash the lens cap and body cap. The clear plastic piece gets the middle cut out to the edges, same with the body cap. Note: I didnt remove the treads that lock the body cap to my camera. Most important. Also take time to note how the bayonet mount of the body cap attaches, so when this is finally assembled your bellows fit on right (i messed up on this part as you'll see later)
cost up to this point, 5$ for the titan body cap from hunts photo and video.