use 'how to install' and center

Author: FoamyGuy

_includes/download/board.html

@@ -50,7 +50,7 @@ <h3>CircuitPython {{ version.version }}</h3>
         <a href="https://github.com/adafruit/circuitpython/releases/tag/{{ version.version }}">Release Notes for {{ version.version }}</a>
       </p>
       {% if page.download_instructions != nil and page.download_instructions != "" %}
-        <a class="download-button install-instructions-button" target="_blank" href="{{ page.download_instructions }}">INSTALL INSTRUCTIONS<i class="fas fa-arrow-circle-right" aria-hidden="true"></i></a>
+        <a class="download-button install-instructions-button" target="_blank" href="{{ page.download_instructions }}">HOW TO INSTALL<i class="fas fa-arrow-circle-right" aria-hidden="true"></i></a>
       {% endif %}
     </div>
     <div class="download-details">

assets/sass/pages/_download.scss

@@ -60,6 +60,7 @@
 
       .install-instructions-button{
         width: 100%;
+        text-align: center;
         margin-bottom: 1em;
       }