redirection issue

I know the answer to the question is out there somewhere, but I haven’t been able to find it over the last 2 hrs of searching. Here is my issue:

If I type in http://domain.org/index.php I am rerouted to the temporary index.htm file that talks about the site being underconstruction instead of going to the home page (index.php) of wordpress.

How can I view the index.php page of wordpress, while keeping it hidden behind a temporary index.htm page while I’m building the wordpress site?

Thanks,
Barb