This is an Ikea Stranda wardrobe that I bought several years ago. It is made from unfinished spruce.
Paint the piece with white paint mixed with baking soda. The ratio to use is 2/3 cup paint to 1/3 cup baking soda. The baking soda should first be mixed with a bit of water to turn it into a paste. Then add the paste into the paint and mix really well.
When the white paint has dried, paint over the white with black paint. Allow to dry for several hours. Use the fine grit side of the sanding sponge and sand in random places to expose some of the white paint and the medium grit sponge to sand right down to the wood on the edges and corners. Wipe the dust off the piece and paint over the black with a satin finish paint in a grey-green shade. Once the top coat of paint has dried, sand the edges and corners again with a fine grit sanding sponge to expose the other two paint colours and the wood. To add to the antique look, wash the dust off using a cloth soaked in vinegar. This makes the paint look streaky and layered.
I used a 1×6 board and a magic marker to draw lines on the panels to make them look like they were made of planks of wood instead of slabs. Then I sanded the panels lightly to make the lines look faded.