Accessing Object Properties with Variables: need more info about this code

Tell us what’s happening:
Hi, I understood how to solve it,
but someone can make me a more detailed explanation of the code?

Your code so far

FIRST PART::


// Setup
var testObj = {
  12: "Namath",
  16: "Montana",
  19: "Unitas"
};

// Only change code below this line;

var playerNumber = 16;       // Change this Line
var player = testObj[playerNumber];   // Change this Line

SECOND PART:

var someObj = {
propName: “John”
};
function propPrefix(str) {
var s = “prop”;
return s + str;
}
var someProp = propPrefix(“Name”); // someProp now holds the value ‘propName’
console.log(someObj[someProp]); // “John”

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.119 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-javascript/accessing-object-properties-with-variables

What is it that you don’t understand?

It’s so simple @pavlo.dyrda

Solution:
var playername=16;

var player = testObj[playername];

Just they gave a detailed explanation of accessing some object values using some variable