Run function on 1 sheet only instead of .forEach - google-apps-script

Question

I believe this will be a super easy question for you. I downloaded a YT script to automatically update YT views on Google Sheets which you can find here (https://developers.google.com/gsuite/solutions/youtube-tracker).
I have a spreadsheet with 12 tabs and the code has a function to go through every tab in the spreadsheet.
function markVideos() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheets = SpreadsheetApp.getActiveSpreadsheet().getSheets();
// Runs through process for each tab in Spreadsheet.
sheets.forEach(function(dataSheet) {
var tabName = dataSheet.getName();
var range = dataSheet.getDataRange();
var numRows = range.getNumRows();
var rows = range.getValues();
var headerRow = rows[0];
I want to change it to apply to a specific tab only, let's say "Sheet12", instead of running it for every tab.
function markVideos() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheets = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Sheet12");
// Runs through process for each tab in Spreadsheet.
function NameOfTheFunction(dataSheet) {
var tabName = dataSheet.getName();
var range = dataSheet.getDataRange();
var numRows = range.getNumRows();
var rows = range.getValues();
var headerRow = rows[0];
I tried this but had no luck because it doesn't seem to be applying the function to the specific sheet. I believe this is super easy fix but I have no idea about programming.

Answer 1

Remove the forEach statement and use getSheetByName instead of getSheets:
function markVideos() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var tabName = 'Sheet12';
var dataSheet = ss.getSheetByName(tabName)
var range = dataSheet.getDataRange();
var numRows = range.getNumRows();
var rows = range.getValues();
var headerRow = rows[0];
}

Answer 2

Array ForEach() Method calls a function once for each element in an array. That is why a function must be defined that will take an array element function(dataSheet)
Since you only need to access 1 sheet based on its sheet name.
You don't need to define a function to access the properties of that sheet.
Sample:
Sample Code:
function myFunction() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheets = ss.getSheetByName("Sheet1");
var tabName = sheets.getName();
var range = sheets.getDataRange();
var numRows = range.getNumRows();
var rows = range.getValues();
var headerRow = rows[0];
Logger.log(tabName);
Logger.log(numRows);
Logger.log(rows);
Logger.log(headerRow);
}
Logger Log Output:
References:
Class Sheet Methods
SpreadsheetApp Methods