Creality Print .3mf files for the K1C, K1 Max, K2 and K2 Pro are provided that ensure the parts are correctly oriented, and each complete piece is on it's own separate plate. You can reorganize these on the larger printers to utilize more of the build surface, if you like.
Settings are 3 walls, 10% gyroid infill. Wall order is outer-inner for dimensional accuracy. Supports are manual. Some parts will use tree, some grid.
Split parts connect together with press-in plugs, which are also arranged on their own separate plate. 44 of them are needed for assembly.
Because I'm impatient, I did not order the drawer slides I saw others recommend, and opted to buy from another source. This did not work out well for me, but I managed to salvage it with the cunning use of heat inset nuts. Again, this remix retains the original screw holes for the drawer slides that it was designed to use, not my janky personal build.
The drawer slides that I've seen recommended (and did not use):
https://www.amazon.com/dp/B07171LBQM/
What you'll need:
If you're using the 3MF files I've provided, then support settings are already fairly optimized, and they should pop off fairly cleanly. Use the supports and tolerances test plate to ensure that everything is good before you waste nearly 2KG of filament. On the parts with tree supports though, you may find a bit of interfacing stuck here and there. Best to use a hobby knife or something to scrape it off.

Use the provided connection plugs (you'll need 44 in total) to snap these pieces together as shown to form complete parts. You shouldn't need glue to hold these in place, but it never hurts.

Once you've assembled your complete parts, assemble the frame. Start by connecting the two back pieces together using 2x 30mm M3 screws.

Then, attach each side piece to the back of the frame. For each side, use 1x 30mm and 2x 25mm screws.

Then fix the top CFS shelf to the frame using 8x 20mm M3 screws. You can ignore two of the six screw holes, four is plenty.

Finally, line your rails up with the bottom part of the frame, and use your 10mm M4 screws to fix it in place, and then fix the bottom CFS shelf in place with 4x (or more, if you feel like it and the holes line up) 10mm M3 screws.
Unfortunately, this is where things fell apart for me. I had to come up with ways to improvise, and my racoon brain lost track of what it was doing and forgot to take pictures.
You can figure it out, I have faith in you. Your end result will look something like this.

You can now either fix your CFS units into place on the trays using 10mm M4 screws. Or not. Do whatever you want. You can technically access the CFS units from underneath with the trays open like this, if broken filament is a thing you deal with often. It's still going to be awkward as all hell to get underneath either of these things, so temper your expectations, yeah?

And that's everything. Hope you found this useful.
The author remixed this model.
I recently picked up a K1 Max and a couple of CFS units, and wanted to print a stand to hold them. I really liked the original design, with it's sliding bottom, as it's perfect for my space. Unfortunately, it needs a 350mm bed in order to print.
So, as a last resort, I chopped it into pieces, like my life.
These pieces connect together with snap-in plugs. The end result is quite sturdy, and it's printable on any machine with at least a 220x220 bed.
I did feel the original is a bit overengineered for what it's meant to hold, so I removed a (lot) of material for the CFS shelves, and a (little) from some of the other parts, closing some screw holes. Otherwise, the design looks and functions mostly the same once it's put together.
This also allows access to the underside of the CFS units. Sort of.