How could I generate the top 3 scores and show them to the participants in the survey?

Hi rhhao,
That code is indeed invalid. All programming languages have specific syntax and methods to do certain things, and most of the lines in that example don't follow those rules. Something like this might have a better chance:
//put "var" in front of each variable, otherwise it won't be defined
//(you'll need to add the remaining values in this array, it is cut off in the screenshot)
var array = ["${QID144/ChoiceNumericEntryValue/1}", "${QID147/ChoiceNumericEntryValue/1}", "${insert the rest of the values}"];

const max1 = Math.max(array);

//find the position of max1 in the array using Array.indexOf()
var m1Pos = array.indexOf(max1);
//delete one element starting from the position of max1 by using Array.splice()
array.splice(m1Pos, 1);

//repeat the process for the remaining max values in "array"
const max2 = Math.max(array);
var m2Pos = array.indexOf(max2);
array.splice(m2Pos, 1);

const max3 = Math.max(array);
This is a very basic example (which I have not tested) and there are better, more efficient ways to do it. But considering you're not familiar with Javascript I felt this might be clearest.
To solve the second part of your question you would need to somehow match the scores to each candidate. I'm not sure how you have your survey set up, but I would first try and gather all of the names from the question in an array similar to how you've gathered the scores. You could then use the index of position of each "max" score you've gathered to find the correct candidate and set it to an embedded field for piping in later.
Expanding on the above code:
var array = ["${QID144/ChoiceNumericEntryValue/1}", "${QID147/ChoiceNumericEntryValue/1}", "${insert the rest of the values}"];
var names = ["${QID144/ChoiceDescription/1}", "${QID147/ChoiceDescription/1}", "etc"]

const max1 = Math.max(array);

//find the position of max1 in the array using Array.indexOf()
var m1Pos = array.indexOf(max1);
//find the candidate with this score and store it as an embedded field
var maxCandidate1 = names.indexOf(m1Pos);
Qualtrics.SurveyEngine.setEmbeddedData( 'maxcandidate1', maxCandidate1 );

//delete one element starting from the position of max1 by using Array.splice()
array.splice(m1Pos, 1);
//remove the candidate so they cannot be chosen again
names.splice(m1Pos, 1);

//repeat for candidates 2 and 3
//...
Again, not the best example, but hopefully it's a clear one.
PS - you may also need to think about what to do in the case of a tied score. By default, Array.indexOf() returns the first match for the value being searched for, so it may select the wrong candidate name if two have the same high score. The relevant documentation may help you figure out a solution.
Good luck!