How to Address by Name

We take variable this_user from Variables section in Botmother, and add the value of the name firstname to it, we get variable this_user.firstname.
We write the text of the message:
Hello, {{this_user.firstname}}
The bot will output such a message to the user:
Hello, John
If you need to output the user's first and last name, use this_user.full_name variable. And if you output only the last name use this_user.lastname.