An Mahogany wardrobe flatpack can be made at a workbench (Bench with vice or better) in the workshop of a player-owned house. Like when making the normal Mahogany wardrobe, this requires 75 Construction, uses 3 Mahogany planks, and gives 420 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 a Mahogany wardrobe flatpack from scratch gives a profit of: -5,116
After completing the hard Fremennik Tasks, they can also be traded to Advisor Ghrim in exchange for 507 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Miscellania reselling for details.