Will index.php go directly to the site

I feel a complete clown asking this question so I am ready for flak. Normally when I build a web site and load it up any browser, I think, goes through to find index.html or, failing that, index.htm and then calls up the blog.
I designed my blog so that it booted from index.htm.
Now I have discovered WordPress (which is so great words fail me) and it has index.php. At the moment I am working with a piece of code which transfers the opening page from my original to the WordPress version. I am not trying to get my site in here but as it is non-commercial – no advertising – it is OK.
The blog is bloggeroff.com.
What I most seriously want to do is not use the piece of transfer code but go straight in. If index.php is the way to go (delete index.htm) then I am doing something wrong and I will work at it.
But nowhere, and I have seriously tried for some considerable time, can I find anything on this subject.
Any pointers will be most gratefully received.

Gareth Powell in Australia