I do not undesrtand templating with handlebars

https://www.codecademy.com/paths/web-development/tracks/build-interactive-websites/modules/templating-with-handlebars/lessons/learn-handlebars/exercises/handlebars-expression

Good day! I wanted to try to make a template with handlebars on my own, but I can not, and I wanted to tave a result string

I want to say Hello!

. Why is my code incorrect?

о