You’ll need to find the new plank and sheet metal items in Arc Raiders for the new Sheltered Retreat project, after you’ve taken a picture of the Ruined Homestead, and are ready to start committing resources.

There are a few ways to get both items:

• Celeste sells planks and sheet metal for three seeds a piece.
• You can find loads of planks in residential and old world areas, particularly in the houses in Old Town in the southwest of Pendola Pass, as well as research items and furniture blueprints, too.
• You can find loads of sheet metal in technological and industrial areas, such as the Assembly and Loading Bay in Stella Montis, where every yellow drawer container (pictured above) seems to be a guaranteed drop for sheet metal.
• You can also find planks and sheet metal in other areas, though less frequently.

Thankfully, you don’t need much for the project, so you might want to simply spend the 24 seeds required to just buy them all from Celeste.