Hi, Use the pick-axe on the iron-ore (Shiny rocks) to get Iron, the iron can be found in your inventory under "Misc".
To get metal resources, you have to use a fire-pit/furnace to smelt the iron you looted, once you click on the smelt button the amount of metal will increase automatically.
Please watch from 0:55 to 1:10 here:
Thanks.
Note: make sure you save and load the using the same character.