boostrap modal properties

Hi there,

From the page below:

https://getbootstrap.com/docs/4.0/components/modal/

I am able to built a modal successfully.  The problem is that I would like the "modal box" to appear (say) 5 centimeters below the place it automatically appears, simply because the upper fixed panel (shown in yellow in the figure attached) "hides" part of the modal box.

What should I include (I guess) here:

<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
                         ---
    </div>
  </div>
</div>

so that I will have the full modal box shown?

Thanks!
fskilnik.
30Nov17_ModalProblem.gif