Trying to create a script editor code for sheet3 only

Question

I'm trying to make a Y/N popup box appear when you open the sheet3 on a Googlesheet file. So far I have this code:

function onOpen() {
  var ui = SpreadsheetApp.getUi();
  var result = ui.alert(
     'Please confirm',
     'Have you sorted the Calculations Page?',
      ui.ButtonSet.YES_NO);

  // Process the user's response.
  if (result == ui.Button.YES) {
    // User clicked "Yes".
    ui.alert('Thank you, you may continue.');
  } else {
    // User clicked "No" or X in the title bar.
    ui.alert('Please sort the Order Number column.');
  }
}

But with this code, it applies when I open the document, and only when I open the document. I'd like it so the box appears when I open the sheet3 tab. Extra points if there is a way to take me to sheet2 if you click 'No' on the box!