how to use ReplyKeyboardMarkup MrRobin ?

[NaderSetarei]

var rkm = new ReplyKeyboardMarkup
{
Keyboard = new[] { new[] { "cmd1", "/cmd1" }, new[] { "cmd2", "/cmd2" } }
};

whats the next step ?

[MrRoundRobin]

var keyboardMarkup = new ReplyKeyboardMarkup
{
    Keyboard = new[]
    {
        new[] // row 1
        {
            "cmd1",
            "cmd2"
        },
        new[] // row 2
        {
            "cmd3",
            "cmd4"
        }
    },
    ResizeKeyboard = true
};

await Bot.SendTextMessage(update.Message.Chat.Id, "Question?", false, 0, keyboardMarkup);
//or
await Bot.SendPhoto(update.Message.Chat.Id, "<photo_id>", "Nice Pic", false, 0, keyboardMarkup);