customize apis list "/apis" page

[apigeesample]

i need add element div contains description to apis list 

what is the best way to do that ?

i add custom script to add div element but it doen't work 

it works only when reload page

window.portal = {};

window.portal.pageEventListeners = {

  onLoad: (path) => {

      var targetDiv = document.querySelector("api-list");

      var newContent = `

    <div class = "product-list-details">

        <h3 class = "page-title">APis List</h3>

`;

      // Check if the target div exists

      if (targetDiv) {

        // Insert the new content before the target div

        targetDiv.insertAdjacentHTML("afterbegin", newContent);

      } else {

        console.error("Target div not found.");

      }

}}