An oak drawers flatpack can be made at a workbench (Oak workbench or better) in the workshop of a player-owned house. Like when making the normal Oak drawers, this requires 27 Construction, uses 2 oak planks, and gives 120 experience. The flatpack can then be used on a wardrobe hotspot in a Bedroom, either in building mode or not. This requires no Construction level and gives no experience.
The cost of making and selling an oak drawers flatpack from scratch gives a profit of: -946
After completing the hard Fremennik achievements, they can also be traded to Advisor Ghrim in exchange for 56 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Miscellania reselling for details.