Run 2 Google Apps scripts

Question

I am brand new to Google App Scripts. I have 1 google sheet, with 2 tabs. I have a timestamp script for each tab sheet. I can't figure out how to make it so that if someone types in a cell, a timestamp will automatically appear.
Thank you in advance for any help.

function onEdit(e){
  myFunction1();
  myFunction2();

function myFunction1();  {
var row = e.range.getRow();
var col = e.range.getColumn();

if(col  === 15 && e.source.getActiveSheet().getName() === "Monthly Reviews"  ){
e.source.getActiveSheet().getRange(row,16).setValue(new Date());

}
function myFunction2();  {
var s = SpreadsheetApp.getActiveSheet();
if( s.getName() == "SLP" ) { //checks that we're on "TABNAME" tab or not
var r = s.getActiveCell();
if( r.getRow() == 7 && r.getColumn() == 2 ) { // checks that the cell being edited is in row 7 column 
2
var nextCell = r.offset(1, 0); // looks at the cell in the 1 row down same column
if( nextCell.getValue() === '' ) // checks if that adjacent cell (1 down) is empty or not?
nextCell.setValue(new Date()).setNumberFormat('MM-dd-yyyy HH:mm:ss'); //sets the timestamp when 
original cell is updated
}
 }
 }

}

Answer 1

function onEdit(e){

  var row = e.range.getRow(),
      col = e.range.getColumn(),
      tmshtCell = null;

  switch (e.source.getActiveSheet().getName()){
    //checks that we're on "TABNAME" tab or not
    case 'Monthly Reviews' :              
      if (col === 15) tmshtCell = e.range.offset(0,1)
    break;
    //checks that we're on "SLP" tab or not
    case 'SLP':
      // checks that the cell being edited is in row 7 column 2 and checks if that adjacent cell (1 down) is empty or not?
      if (row === 7 && col === 2 && e.range.offset(1,0).getValue() == '') tmshtCell =e.range.offset(1,0)
    break;
  }
  if (tmshtCell) tmshtCell.setValue(new Date()).setNumberFormat('MM-dd-yyyy HH:mm:ss')

}

Answer 2

function onEdit(e) {
  const sh = e.range.getSheet();
  if (sh.getName() == "Monthly Reviews" && e.range.columnStart == 15) {
    e.range.offset(0, 1).setValue(new Date());
  }
  if (sh.getName() == 'SLP' && e.range.columnStart == 2 && e.range.rowStart == 7) {
    if (e.range.offset(1, 0).getValue() == '') {
      e.range.offset(1, 0).setValue(new Date());
    }
  }
}

Note: You cannot run this function from the script editor unless you supply the event object.