Buttons to select checkboxes by name

I have the following checkboxes in an HTML form.

<ul id="selection">
  <span><label>First<br><input type="checkbox" name="First"></label></span>
  <span><label>Second<br><input type="checkbox" name="Second"></label></span>
  <span><label>Third<br><input type="checkbox" name="Third"></label></span>
  <span><label>Fourth<br><input type="checkbox" name="Fourth"></label></span>
  <span><label>Fifth<br><input type="checkbox" name="Fifth"></label></span>
</ul>

I'm trying to create two buttons. One that would select the first two and one that would select all of them.
I managed to select all of them with one button using this:

<input type="button" class="check btn" onClick="select(this)" value="Select All"/>
    <script>
      $('.check:button').click(function(){
          var checked = !$(this).data('checked');
          $('input:checkbox').prop('checked', checked);
          $(this).val(checked ? 'uncheck all' : 'Select' )
          $(this).data('checked', checked);
      });
    </script>

But I can't seem to get the two buttons working.
My JavaScript knowledge is pretty limited and been searching for days, unsuccessfully for a solution that works.
Can please someone help? a detailed explanation would be awesome.