li>First create your <code>.tsx</code> file, say &quot;hello.tsx&quot;, and export a <code>subapp</code> that&#x27;s a <code>ReactSubApp</code> type:</li></ol><div class="language-tsx codeBlockContainer_Op_Y theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_aGc1"><pre tabindex="0" class="prism-code language-tsx codeBlock_QQ5Q thin-scrollbar"><code class="codeBlockLines_H6Zg"><span class="token-line" style="color:#bfc7d5"><span class="token keyword"