add how to play link

src/client/index.html

@@ -31,7 +31,16 @@
 		<h2 class="text-3xl sm:text-4xl md:text-5xl lg:text-6xl mb-4">(v0.9.0)</h2>
 		<div class="flex justify-center items-start">
 			<div class="w-full max-w-3xl p-4 space-y-4">
+				<br />
 				<username-input></username-input>
+				<div class="flex space-x-2 max-w-xs mx-auto">
+					<a href="https://www.youtube.com/watch?v=A4QRo-xRlkM" id="how-to-play" target="_blank"
+						rel="noopener noreferrer"
+						class="flex-1 px-4 py-2 text-lg font-bold text-white bg-emerald-600 hover:bg-emerald-700 rounded-mg focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-green-500 transition duration-300 ease-in-out text-center">
+						How to Play
+					</a>
+				</div>
+				<br />
 				<!-- Button layout -->
 				<div class="flex space-x-4 max-w-xs mx-auto">
 					<!-- Single Player button -->