For enabling devcommands..

1) Go to valheim properties in your library. Under general tab, in the launch options, type
-console
2) In the game itself, hit F5, type devcommands
3) Variety of commands. For spawning it is " spawn [item name] [amount]
ie what i did earlier today because my onions vanished..

spawn onion 16

or for you
spawn IronScrap 600
At the bottom of the console it includes some autofill options for items. Not all items will offer an autofill, specifically metal like iron and bronze. Press Tab to cycle through them

other commands include fly, god, ghost (you have no aggro range), killall, tameall (iirc)