file link-up issue fixes

Author: wowrakibul

.DS_Store

@@ -19,7 +19,7 @@
                 <h1>EcoQuest</h1>
                 <h2>The Green Adventure</h2>
                 <button id="start-game">Start Game</button>
-                <button id="how-to-play" class="secondary" onclick="window.location.href='/guide/how-to-play.html'">How
+                <button id="how-to-play" class="secondary" onclick="window.location.href='./guide/how-to-play.html'">How
                     to Play</button>
             </div>