Difference between newline and carriage return?

Tell us what’s happening:
I know what I need to do, they showed it on the example. My only question is what the difference is between newline and carriage return. They both seem the same to me, and it really confuses me why both are used in succession.

Your code so far

var myStr = "FirstLine\n \SecondLine\ ThirdLine"; // Change this line

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