How to make ReplyKeyboardMarkup with telegram-bot-api Golang

Only one information I found is closed thread from 2015 with problem in library. There was a piece of code

itemsSel := [][]string{}
itemsSel = append(itemsSel, []string{item1.Caption, item2.Caption, item3.Caption})
msg := tgbotapi.NewMessage(update.Message.Chat.ID, "Select item")
msg.ReplyMarkup = &tgbotapi.ReplyKeyboardMarkup{
    Keyboard:       itemsSel,
    ResizeKeyboard: true,
    OneTimeKeyboard: false,
    Selective:       false,
}
log.Println(msg.ReplyMarkup)
msg.ReplyToMessageID = update.Message.MessageID
bot.Send(msg)

There is some description of tgbotapi.ReplyKeyboardMarkup object, but there is a matrix of KeyboardButton objects as it is written on https://core.telegram.org/bots/api#replykeyboardmarkup. How to make this object, I don't know. Help me :3

Hello this is how I did it

1. Define your reply keyboard with all its rows and buttons in rows

   var itemsSel = tgbotapi.NewReplyKeyboard(
     tgbotapi.NewKeyboardButtonRow(
       tgbotapi.NewKeyboardButton("button1"),
       tgbotapi.NewKeyboardButton("button2")),
   )

2. then you define your message config

   msg := tgbotapi.NewMessage(update.Message.Chat.ID, "Main Menu")

3. assign your Reply Keyboard to the Message Reply Markup like this

   msg.ReplyMarkup = mainMenu

4. Send it

   bot.Send(msg)

I learned all that from some Ukrainian youtuber
Here is the video https://www.youtube.com/watch?v=yJkzK1-fLf4