1. Open the manifest.json file found in your project root directory under Packages > manifest.json
2. Add "com.medallyon.savemanager": "https://github.com/medallyon/unity-savemanager.git", to the dependencies object.
3. Go back to Unity and allow it to install the package into your project.

1. In the Unity Editor, open the Package Manager window (Window > Package Manager).
2. Click the ➕ sign in the top-left corner of the Package Manager and select Add package from git URL...
3. Insert https://github.com/medallyon/unity-savemanager.git and click Add.

isFirstLoad denotes whether a Data file was found and loaded. If this evaluates to true, the data parameter will not contain any entries, and it usually means that this is the first time that the game was started. If this evaluates to false, the data parameter will contain entries for all variables that are decorated with the [Save] Attribute in this MonoBehaviour.

The data parameter is a Dictionary that maps the name (string) of the Saved Field or Property to its value (object). You will have to cast the value into the desired type. For complex values, you may have to do more processing using methods from the Newtonsoft.Json Assembly, such as JsonConvert.DeserializeObject<T>. More samples will follow illustrating how to cast this data properly.

Since the data parameter is a Dictionary, we can use its indexer to access Variables via their names. Here, the C# nameof keyword comes in handy. See the following example on how to access the saved _playerID variable:

public class MySaveableComponent : MonoBehaviour, ISaveable
{
    [Save] private Guid _playerID = Guid.Empty;

    // This happens before 'Start' is called
    public void OnRestore(bool isFirstLoad, Dictionary<string, object> data)
    {
        // If the '_playerID' Variable was never saved, use a desired default Value
        if (isFirstLoad)
        {
            _playerID = Guid.NewGuid();
            return;
        }
        
        // Get the name of the saved Variable as a string ("_playerID")
        string variableName = nameof(_playerID);
        
        // Access the value of the saved Variable through the Dictionary's indexer
        string variableValue = (string)data[variableName];
        
        // Parse the string Value as a 'Guid' and set the Value for '_playerID'
        _playerID = Guid.Parse(variableValue);
    }
}

The contents of OnRestore in the above example could also be condensed into a single statement:

_playerID = isFirstLoad ? Guid.NewGuid() : Guid.Parse((string)data[nameof(_playerID)]);