This is an example of nestled tags:
This is bold, but this is italic. Also, this is not bold but this is underlined!
Tags can be nestled any way you like, as long as you close the tag properly and in the right place.
You already know how to nestle tags... notice how the <body> element is nestled within the <html> element. Simple! Later, it will become second nature to nestle tags. You won't even notice you're doing it!