specified applying a manifest (closes #226)

index.html

@@ -730,6 +730,27 @@ <h3>
           </li>
         </ol>
       </section>
+      <section>
+        <h3 id="applying">
+          Applying the manifest
+        </h3>
+        <p>
+          A <a>manifest</a> is <dfn>applied</dfn> to a <a>top-level browsing
+          context</a>, meaning that the members of the <a>manifest</a> are
+          affecting the presentation or behavior of a browsing context.
+        </p>
+        <p>
+          A <a>top-level browsing context</a> that has a manifest applied to it
+          is an referred to as <dfn>application context</dfn>. When an
+          <a>application context</a> is created, its <a>session history</a> is
+          empty.
+        </p>
+        <p>
+          The appropriate time to <a title="applying">apply</a> a manifest is
+          when the <a>application context</a> is created and before navigation
+          to the <a>start URL</a> begins.
+        </p>
+      </section>
       <section id="updating">
         <h3>
           Updating the manifest