Adding JavaScript to Button

I'm trying to add a JavaScript to a button to bring up a BackerKit pre-order store. An example of what I'm trying to do (though I don't think it's a Squarespace site): top right corner of https://lynqme.com/

With the code provided below from BackerKit in a code block I was able to get things to work with clickable "Pre-order Now" text...

<script>
    (function() {
      var script = document.createElement('script');
      script.src = 'https://backerkit.com/assets/preorders.js';
      script.async = true;
      var entry = document.getElementsByTagName('script')[0];
      entry.parentNode.insertBefore(script, entry);
    })();
</script>

<a href="#" data-bk-preorders="https://virtueathletic.backerkit.com/overlay_preorders">Pre-order Now</a>

...and with my own fumbling through additional code I was able to get the text to kind of be a button.
<script>
    (function() {
      var script = document.createElement('script');
      script.src = 'https://backerkit.com/assets/preorders.js';
      script.async = true;
      var entry = document.getElementsByTagName('script')[0];
      entry.parentNode.insertBefore(script, entry);
    })();
</script>
<div align="right" class="sqs-block button-block sqs-block-button">
<a href="#" data-bk-preorders="https://virtueathletic.backerkit.com/overlay_preorders" class="sqs-block-button-element—small sqs-block-button-element">Pre-order now</a>
</div>

Unfortunately I can't get the button to look, function, and align like my regular button blocks (blue/white & white/black on hover) as seen in the attached image (blue button block on top - black JavaScript "button" on bottom.)
 

OP Update:

I was able to get a button functioning with the following code, but unfortunately it cause all other media on the page to not load. If this is in there as a code block, any page it's on only displays as the grey background color with no banner images or videos.

<div class="sqs-block button-block sqs-block-button" data-block-type="53" id="block-bkstore”>
    <div class="sqs-block-content" id=“bkstore”><div class="sqs-block-button-container--right" data-animation-tier="2" data-alignment="right" data-button-size="small" id=“bkstore”>
        <a href="#" data-bk-preorders="https://virtueathletic.backerkit.com/overlay_preorders" class="sqs-block-button-element--small sqs-block-button-element" target="_blank" data-initialized="true">Pre-Order Now</a>
        </div>
    </div>
</div>

OP Update #2:

I think I got it. Code block:

<div class="sqs-block button-block sqs-block-button">
  <div align="right">
  <a href="#" data-bk-preorders="https://virtueathletic.backerkit.com/overlay_preorders" class="sqs-block-button-element--small sqs-block-button-element" target="_blank">Pre-order Now</a>
  </div>
</div>