The Resource Loader mod is meant to be used with the Custom Main Menu and Custom Background mods, and all three are from the same author, so they are all highly compatible with each other. However, Resource Loader works well with practically any mod where the config file allows you to set resource locations and parameters. Essentially, this mod lets you add your own resources to Minecraft, without forcing you to create a resource pack. It works in much the same way, but you don’t see your resources from this mod in your resource pack window like you see normal packs.
After installing Resource Loader Mod, simply run Minecraft for a minute, then close the game. The next time you run Minecraft, you’ll see a new folder in your main Minecraft folder, called “resources”. That’s the folder where you’ll dump your new resources, whatever those might be. Then they’ll show up in Minecraft like they normally would with a resource pack. This sounds a bit simpler than it actually is – you’ll need some technical knowledge about the way Minecraft works before you can add resources to your game seamlessly. The best way to learn is to practice though, so just follow the author’s instructions.