using StackExchange.Redis;

// ...

// connect to the server
ConnectionMultiplexer connection = ConnectionMultiplexer.Connect("localhost");

// select a database (by default, DB = 0)
IDatabase db = connection.GetDatabase();

// run a command, in this case a GET
RedisValue myVal = db.StringGet("mykey");

class Program
{
    private static Lazy<ConnectionMultiplexer> _multiplexer =
        new Lazy<ConnectionMultiplexer>(
        () => ConnectionMultiplexer.Connect("localhost"), 
        LazyThreadSafetyMode.ExecutionAndPublication);

    static void Main(string[] args)
    {
        IDatabase db1 = _multiplexer.Value.GetDatabase(1);
        IDatabase db2 = _multiplexer.Value.GetDatabase(2);
    }
}

Connect to Redis server and allow admin (risky) commands

ConfigurationOptions options = new ConfigurationOptions()
            {
                EndPoints = { { "localhost", 6379}},
                AllowAdmin = true,
                ConnectTimeout = 60*1000,
            };
ConnectionMultiplexer multiplexer = ConnectionMultiplexer.Connect(options);

or

ConnectionMultiplexer multiplexer = 
    ConnectionMultiplexer.Connect("localhost:6379,allowAdmin=True,connectTimeout=60000");

Connect to Redis server via SSL

 ConfigurationOptions options = new ConfigurationOptions()
            {
                EndPoints = { { "localhost", 6380}},
                Ssl = true,
                Password = "12345"
            };
ConnectionMultiplexer multiplexer = ConnectionMultiplexer.Connect(options);

or

ConnectionMultiplexer multiplexer =
     ConnectionMultiplexer.Connect("localhost:6380,ssl=True,password=12345");