Discovering the WorkshopTo start off, you will need to head to Seers' Village and enter the house located southwest of the bank. Once you reach the house, search the bookcase, and you will find a Battered Book.
Read the book to find out, "You may still find a way to enter the workshop within this leather bound volume." Grab a knife from the nearby table then use it on the book to find a key. Head to the building just north with the anvils and use the Battered key on the "Odd looking wall".
Preparing to Make a Shield
From the main room, head west. Once you are in the west room, mine an elemental rock. You will attempt to mine the rock and it will turn into an Earth Elemental. Kill it and collect the Elemental ore.
Head into the northern room. Turn both wheels then pull the lever. Search the crates around the place until you find some leather. Now go into the east room and "Fix Bellows" with your leather, then pull the lever.
After you do the above, head to the main room and search the boxes in the northeast corner. You should get a stone bowl.
Making an Elemental Shield
Head to the south room with your stone bowl. Use the bowl with the lava trough to fill it up with lava. Next use your filled stone bowl with the furnace located in the eastern side of the room.
Use your 4 coal and Elemental ore with it to make an Elemental bar. Finally, head to the main room with a hammer, and use your Elemental bar with a workbench to make an Elemental shield!