...
import static com.github.crimsondawn45.fabricshieldlib.initializers.FabricShieldLibClient.renderBanner;
...
public class ExampleModClient implements ClientModInitializer {
	...
	@Override
	public void onInitializeClient() {
                ...
		BuiltinItemRendererRegistry.INSTANCE.register(ExampleMod.NETHERITE_BANNER_SHIELD, (stack, mode, matrices, vertexConsumers, light, overlay) -> {
			renderBanner(stack, matrices, vertexConsumers, light, overlay, modelNetheriteShield, NETHERITE_BANNER_SHIELD_BASE, NETHERITE_BANNER_SHIELD_BASE_NO_PATTERN);
			//The first five parameters are taken from the method, while the last 3 you provide yourself. 
			//You will provide the model, and then your 2 sprite identifiers in the order of SHIELD_NAME_BASE and then SHIELD_NAME_BASE_NOPATTERN.
		});
		...
	}
        ...
}