Assemble the bays using the steps below.
Wash the grease off the threaded rods with soap and hot water. They will almost certainly arrive coated in grease, and these are stainless steel parts being used in a dry environment. Leaving it on will just end up with the whole project being greasy.
Cut each rod to 405 mm long. If you haven’t done this before this is the best way to do so that I’ve used if you’re using a hacksaw . I recommend a chop saw, however.
Thread a hex nut around 15 mm in, doing so on the side you cut, followed by a wing nut with the wings facing inward / towards the long side. The exact distance doesn’t matter as long as all the hex nuts are roughly the same. Don’t worry about getting them exactly the same now, as it is better to fine tune it after all the parts are together.