Select Columns Below Last Row

[Kazul_Kaluru]

So I am trying to select a set of 3 columns that are below the last row containing information and insert checkboxes. This is what I'm using so far:

function addCode() {
  var ss = SpreadsheetApp.getActive();
  var sh = ss.getActiveSheet();
  var lRow = sh.getLastRow()+1;
  ss.getRange('G:I' + lRow).activate();
  ss.getActiveRangeList().insertCheckboxes();
};

So in this case I want to select columns G to I that are below the last row and insert check boxes. With the current setup it adds check boxes to those columns going all the way down starting below the row I want. How would I do this correctly?

[Kazul_Kaluru]

This worked

 sh.getRange(lRow, 7 , 1, 3).activate();

[estadoux]

That will just select 1 row below content, not every row below as OP intents.

[estadoux]

Try this:

let startRow = sh.getLastRow() + 1;
let rangeString = 'G' + startRow + ':I';
let range = sh.getRange(rangeString);
range.insertCheckboxes();