This is Link's Hylian shield from The Legend of Zelda: A Link to the Past. I've made a few changes from the game art such as adding wood grain and rivets. Feel free to make it your own. I will likely be refining the template soon.
Step 1: Tools and Materiels
For this build you will need:
hot glue gun
1 sheet of foam floor mat 12" x 12"
2 sheets of 5mm craft foam
1 sheet of self adhesive 2mm craft foam
20 round plastic furniture bumpers
Paints: black, red, blue, brown, gold, silver
Step 2: Template and Foam
We all have different means of printing so I've provided the full template as well as a break down. It needs to be printed at actual size/full size. Regardless of how you print it, the template should be cut out and assembled.
Trace the shield full size/assembled on to the EVA foam floor mat. Fold the template in half and cut the border off. Trace the border onto the back and front of the foam floor mat piece. Assemble pieces using contact cement.
Draw wood grain details onto front and back of shield. Be sure to include a few lines to show multiple boards of wood. Score wood details with a sharp blade.
Trace and cut out shield emblems onto self adhesive craft foam. Use the template outline to help position the emblems. Use plastic furniture bumpers for "rivets" around the shield border. Measure and cut two strips of 2mm EVA foam for the arm straps. There is no template for this part as it will vary depending on your arm size.
Step 3: Sealing and Painting
EVA foam is very porous which causes difficulty when paint. This can be addressed by sealing the pores. First, use a heat gun, this will shrink the foam a bit causing the pores to mostly close. Using the heat gun will also accentuate the wood grain details as well as add a curve to the shield. Flex the shield after it's been heated, hold that position until it cools down, it will retain its new shape.
Next you can seal it further using Elmer's Glue, wood glue, Plasti Dip, or even Mod Podge. Use flex seal to fill gaps in seams. Once the shield is sealed, you can begin paint. You'll need a medium to dark blue, brown, black, silver, and gold.
Step 4: Weathering (optional)
Once the whole shield is assembled and painted, you may decide it needs to look used. Use black oil paint and brush it into the nooks and crannies, then wipe with a damp paper towels. There will be some black paint remaining making it grimy. You can try brown and orange for a rusty effect.