With in5, you can create a layout in InDesign and export it as HTML5. The exported content is placed in a generated folder named "html5_output" that contains the index.html file (and numbered files if you select the Multi-page Web output option) and an assets folder that contains a CSS folder, a JS folder, and an images folder. It may also include a downloads folder (if you select to include a downloadable PDF) and a media folder (if you add video assets).
If you only add the index.html content into a Divi code module, the rest of the content in the assets folder won't be included. The content in the assets folder is necessary to make your exported in5 content appear and function as you designed in your layout.
In your previous email, you asked about relinking the contents after splitting the html from the assets folder.
You are welcome to try splitting it apart--just as you're welcome to customize the content that in5 exports. However, splitting the HTML from the assets folder is not an approach that we would recommend nor be able to support if you ran into any issues as a result of the splitting.
An alternative would be to upload your in5-exported content to a web server directly instead of using WordPress. The following article includes links to a variety of paid and free hosting options and links to more information about uploading content: