If you can turn a directory into a HTML page, then you’re almost there. You just have to add the rachel-index.php file to your directory so that the RACHEL front page can see it. The file is here on github – but it does assume familiarity with HTML. If you are not familiar with HTML then it will not really be possible to walk you through it on the forums here.
If you are able to add the rachel-index.php, you would then upload the whole directory to /var/www/modules on the RACHEL-Pi, and it should show up. Hope that is a little helpful!