Below is example of accordion section which is used in some of sections in landing pages.

<div class="panel-group" id="accordion" role="tablist">
<!-- panel -->
<div class="panel">
<div class="panel-hd">
<a role="tab" data-toggle="collapse" data-parent="#accordion" href="#collapse-1" aria-expanded="true">
TITLE OF PANEL
<i class="panel-open fa fa-plus-circle"></i><i class="panel-close fa fa-minus-circle"></i>
</a>
</div>
<div id="collapse-1" class="panel-collapse collapse in" role="tabpanel">
<div class="panel-body">
... COTNENT OF PANEL ...
</div>
</div>
</div><!-- /.panel -->
<!-- panel -->
<div class="panel">
<div class="panel-hd">
<a role="tab" class="collapsed" data-toggle="collapse" data-parent="#accordion" href="#collapse-2" aria-expanded="true">
....
<i class="panel-open fa fa-plus-circle"></i><i class="panel-close fa fa-minus-circle"></i>
</a>
</div>
<div id="collapse-2" class="panel-collapse collapse" role="tabpanel">
<div class="panel-body">
...
</div>
</div>
</div><!-- /.panel -->
</div>
- Apply ID on main parent element as display in line no.1.
- Use that parent element ID in data-parent=”#accordion” attribute as display in above code line no.6
- Apply ID on all panels as display in above code line no.11. Use that ID in href=”#collapse-1″ as display on line no.6