You can just teach them and let them follow you. Children have a good memory. Please say it several times.

You say hello to everyone! Let them say hello teacher (or your name)

Remember, the right child will be rewarded and remembered.

Then use Hello to play games (if you talk about this word in this class)

If you teach songs, look at some nouns in the songs. Just like a bear, you can say hello bear hello cat to your child. ...

Then you can tell the children to play cards or shoot cards. Finally, after the game, you can also say goodbye to the bear and goodbye to the cat while collecting the card. . .

Finally, teach words with actions. Make it easy for children to remember.