Like this... Have you already tried?
First hold press ALT and type on the numpad: 1, 5, 0
Then loose ALT, you will see nothing.
Then press ALT again and hold it, then type on the numpad: 2, 1, 6
Then loose ALT again, then you will see a big A on the chat.

Do you understand now?

If it is not working, then try make your keyboard in different language. Please make it in English (United States (International)), then try again.