How to automatically set a value in drop-down list based on a value from another cell in row - apps script

In my task list each row includes a timeline dropdown menu (F) and a do date cell (K). I want the Timeline dropdown to automatically change based on the date in the do date column.

For example I would like the timeline dropdown to change to Today if the date in the do date column is today's date. I would also like the timeline dropdown to change to Tomorrow if the date in the do date column is tomorrow's date.

I've tried to create the code based on the responses in a few other different forums. However, I have not been able to successfully create the function.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-html -->

function onEdit(event)  // 
{
  var ColK = 11;  // Column Number of "K"
var now = new Date();
  var changedRange = event.source.getActiveRange();
  if (changedRange.getColumn() == ColK) 
  {
    // An edit has occurred in Column K
    var state = changedRange.getValue();
    var Group = event.source.getActiveSheet().getRange(changedRange.getRow(),ColK-5);
    switch (state) 
    {
      case "now”:
        // Select TODAY from dropdown list
        Group.setValue("TODAY");
        break

    }
  }
}

<!-- end snippet -->

Try:

Try something like this, you may add your other conditions.

function onEdit(event){
  var colK = 11;  // Column Number of "K"

  var changedRange = event.source.getActiveRange();
  if (changedRange.getColumn() == colK) {
    // An edit has occurred in Column K

    //Get the Do date and current date then set as same time.
    var doDate = changedRange.getValue().setHours(12, 0, 0);
    let today = new Date().setHours(12, 0, 0)

    //Get the difference of the 2 dates
    var dateDifference = Math.round((doDate - today) / 8.64e7)

    //Set value to dropdown depending on difference
    var group = event.source.getActiveSheet().getRange(changedRange.getRow(), colK - 5);
    if (dateDifference == 0) {
      group.setValue("Today");
    } else if (dateDifference == 1) {
      group.setValue("Tomorrow");
    }
  }
}

Result:

Let me know if this helps!

A start:

function onEdit(e) {
  const sh = e.range.getSheet();
  if(sh.getName() == "Your Sheet Name" && e.range.columnStart == 11 && e.range.rowStart > 3 && e.value) {
    //this will detect a user edit in column K and row > 3 what you wish to do with it is upto you
  }
}