// Initialize the member properties for the newly joining member
const char* playerColorPropertyKey = "PlayerColor";
const char* playerColorPropertyValue = MyGame::GetPlayerColorString(localUser);

PFLobbyJoinConfiguration joinConfig;
joinConfig.memberPropertyCount = 1;
joinConfig.memberPropertyKeys = &playerColorPropertyKey;
joinConfig.memberPropertyValues = &playerColorPropertyValue;

// Join the lobby using the connection string
HRESULT hr = PFMultiplayerJoinLobby(
    g_pfmHandle,
    &localUser,
    connectionString,
    &joinConfig,
    nullptr,
    nullptr);