Match Characters that Occur Zero or More Times Explanation please

Tell us what’s happening:
Why do I have to put “A” and then a “a”?
Why I can’t just write /a*/

Your code so far

let chewieQuote = "Aaaaaaaaaaaaaaaarrrgh!";
let chewieRegex = /Aa*/; // Change this line
let result = chewieQuote.match(chewieRegex);

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Link to the challenge:

in this way you are matching an upper case A followed by zero or more lower case a
it is the only way to match the required string and to not match the strings you should not match