This is for those who could not afford Worbla.
1-Trace and cut the pattern onto the EVA/Craft Foam. You could find many patterns online that has Zelda's Pauldrons. (I will post mine soon in the future but its the WiiU version though.)
2- Attach the parts together. To curve it, use a heat gun to make the foam bit soft to mold on your shoulder/arm. Stabilize it a little with some plaster strips on the inside. Sculpt the raised details with Model Magic, it helps if you wet your fingers to smooth out seams. Adhere it on to the foam with glue or wet the underside til its sticky enough. Let your Model Magic dry completely before putting some sealant (like Modge Podge, Elmers Glue, gesso) to seal the foam.
When working with Model Magic with resin: (I repeat) Remember to let the Model Magic dry COMPLETELY or else when you resin coat it, the model magic would warp and shrink with the resin which will make it wrinkly...
3- Painting! Either brush it on or spray paint would do as long as its gold.
4- Age the armor with a mixture of black and gold paint (or black with very dark green) to give it the worn out look. Paint some of the edges that you want to age and quickly use a wet cloth to wipe off the excess. Finally top it off with some resin coating and gems.
....That wasn't so bad was it?