Flame has a proposed structure for your project that includes the standard Flutter assets directory in addition to some children: audio, images and tiles.

If using the following example code:

void main() {'explosion.mp3');

  final map1 = TiledComponent.load('level.tmx', tileSize);
  final map2 = await SpriteFusionTilemapComponent.load(
    mapJsonFile: 'map.json',
    spriteSheetFile: 'spritesheet.png'

The following file structure is where Flame would expect to find the files:

└── assets
    ├── audio
    │   └── explosion.mp3
    ├── images
    │   ├── enemy.png
    │   ├── player.png
    │   └── spritesheet.png
    └── tiles
        ├── level.tmx
        └── map.json

Optionally you can split your audio folder into two subfolders, one for music and one for sfx.

Don’t forget to add these files to your pubspec.yaml file:

    - assets/audio/explosion.mp3
    - assets/images/player.png
    - assets/images/enemy.png
    - assets/tiles/level.tmx

If you want to change this structure, this is possible by using the prefix parameter and creating your instances of AssetsCache, Images, and AudioCache, instead of using the global ones provided by Flame.

Additionally, AssetsCache and Images can receive a custom AssetBundle. This can be used to make Flame look for assets in a different location other the rootBundle, like the file system for example.