Hi there !
I made this prop for a cool shop next to where I live in Valence (FR), it's called "Lignarius", the idea was to bring more Lord of the Rings vibes on site, so I crafted them one Rohan and one Gondor shields :)
I made it mostly out of EVA foam. I placed a cardboard in the middle (think of it as a sandwich), to reinforce the EVA shape. Then carved out details with a dremel. The wood planks part was easy to sculpt, but the leather side was quite trickier as I has to get more random worn damages, for that I used various metal-sanding heads and fiberglass polish to get subtle surface smoothing variations.
Then I painted the prop as I would paint in photoshop : mix colors, try things, use various paint tools (old worn brushes, pieces of clothes, and vary the amount of acrylics I dropped on every strokes)
As always I added a dirt pass to unify the pieces and get a more believable prop, with a few drops of water to smudge blacks/dark paints on a few points, follow wood fibers...etc. For the gold I used 3 layers of cospaints (1st=espresso gold, 2nd=gallant gold, latest=14k gold , which respectively tinted out as brown, pink, and yellow golds. I believe having breaks even there helps selling the result)
I then used leather for the grab and back straps, it's all worned using sandpaper and a leather carving tool to get nice damage cuts :)