show a modal pop up for 10 seconds or until a flag or variable is set

I am a beginner in jquery so pardon for the mistakes. I want to show a modal pop up for 10 seconds or until a flag or variable is set, then hide this modal pop up and then open another one depending on the flag or variable. Here is the code that I have done so far,

$(document).ready(function() {
$("#btnopen").click(function() {
    $('#myModal1').modal('show');

    setTimeout($('#myModal1').modal('hide'), 10000);  //show myModal1 for 10 seconds
  if({{ flag }}){
    $('#myModal1').modal('hide');
   $('#myModal2').modal('show');  //If flag is set close myModal1 and open myModal2
}
else{
      $('#myModal1').modal('hide');
    $('#myModal3').modal('show');  //else close myModal1 and open myModal3
}
});
$("#btnClose1").click(function() {
  $('#myModal1').modal('hide');
});
$("#btnClose2").click(function() {
  $('#myModal2').modal('hide');
});
$("#btnClose3").click(function() {
  $('#myModal3').modal('hide');
});});

The issue now I am facing is I cannot show myModal1 for 10 seconds. I have searched some documents but nothing solved my problem. Can anyone help me?.
Edit
What should I do if I want the myModal1 pop up close only after the flag is set else, after 30 seconds close myModal1 pop up and open myModal3 pop up. Thanks in advance.

Try the code, this may help you

var myVar;
    $(document).ready(function () {
      $("#btnopen").click(function () {
        $('#myModal1').modal('show');

        myVar=setTimeout(function(){
    $('#myModal1').modal('hide');

    if (flag){
        $('#myModal1').modal('hide');
        $('#myModal2').modal('show');  //If flag is set close myModal1 and open myModal2
      }
    else{
        $('#myModal1').modal('hide');
        $('#myModal3').modal('show');  //else close myModal1 and open myModal3
      }
        }, 10000);  //show myModal1 for 10 seconds

    });


    $("#btnClose1").click(function () {
      $('#myModal1').modal('hide');
clearTimeout(myVar);
    });
    $("#btnClose2").click(function () {
      $('#myModal2').modal('hide');
clearTimeout(myVar);
    });
    $("#btnClose3").click(function () {
      $('#myModal3').modal('hide');
clearTimeout(myVar);
    });

    });

Do not put the following code just after setTimeout(function(){},10000); because the following code will get execute just after setTimeout(function(){},10000); and will not wait for 10 sec. this is an async execution will callback after 10 sec

if({{ flag }}){
    $('#myModal1').modal('hide');
   $('#myModal2').modal('show');  //If flag is set close myModal1 and open myModal2
}