If you’re ever working with something that might catch on fire, you’ll probably want to give it a fireproof shell. The following is a simple reference :)
This took us ~4 hours with terrible planning (ie miscut wood) and missing tools. With proper planning/measurements, you could probably get it done within an hour. The basic design philosophy is to create a firm wooden frame and encase with drywall as a fire retardant.
Before heading to the hardware store, you probably want to make some measurements and draw a schematic beforehand. At minimum, you should get 7 2x4s and 2 2x2s for a two-layer shelf - we bought one 2x4 too few and had to hack around it later. It’s pretty easy to cut pieces down to proper size with a circular saw or a Dremel blade, just make sure the blade is specifically made for wood (a metal blade might chip off and lodge itself somewhere unwanted).
The wooden frame is pretty self explanatory; just build the shape you need. We ended up adding support on the top and bottom to stabilize. Also take note of the height you want each shelf to be at. If you want one layer at standing desk height, consider placing the layer a little lower - your items be placed on top of this layer, and will sit a few inches higher.
Drywall is mainly held together by the thin paper (with one side stronger than the other). Find the stronger side and make a thin cut with a utility knife - it should cleanly split off, after which you can cut the remaining paper piece. Adding drywall will make the shelf significantly heavier, so consider moving the shelf closer to its final location before you install. It’s always best to fully encase the layer with drywall, but if needed, prioritize the upper section since fire always moves upward.
Once everything is in place, you populate the shelf and drill holes as needed!