How to Identation

at HTML Basic 2, there is lesson 2 about identation. however, I am not sure how to make the vertical line to mark which is inside which like that. I have tried space, enter, tab, but it doesnt give me the vertical line. Anyone got any idea how to do it?

the vertical line is not important, most important is you indent your code so your code is good readable. You will find yourself write little code (or actually no code at all) in the codecademy IDE