static function CreateLeaderboard () : ILeaderboard

Description

Create an ILeaderboard instance

void DoLeaderboard () {
    m_Leaderboard = Social.CreateLeaderboard();
    m_Leaderboard.id = "Leaderboard01";
    m_Leaderboard.LoadScores(result => DidLoadLeaderboard(result));
}

void DidLoadLeaderboard (bool result) {
    Debug.Log("Received " + m_Leaderboard.scores.Length + " scores");
    foreach (IScore score in m_Leaderboard.scores)
        Debug.Log(score);
}

Or a little bit differently:

ILeaderboard leaderboard = Social.CreateLeaderboard();
leaderboard.id = "Leaderboard01";
leaderboard.LoadScores (result => {                
    Debug.Log("Received " + leaderboard.scores.Length + " scores");
    foreach (IScore score in leaderboard.scores)
        Debug.Log(score);
});