Changing only the homepage

I need to alter my homepage to look different from the rest of my site. I have tried creating a directory in my template directory and dropping a copy of tpl_main_page.php into it and it works for altering the homepage, but then also alters the my categories and products page. Is there anyway to just alter my homepage without altering these other pages? Thanks.

In that file find a declare for your items "$this_is_home_page"

What do I do from there?

Create the statement for the items that you only want oin your homepage

Read the commented items for guidance

What is it** exactly** that you want as your title "Changing only the homepage" leaves it wide open

I want to use the blank sidebox with some information in it to be wider than the other sideboxes on the left side in a two column layout. I also need it to line up with the featured product box so it stays lower than the main content box. I only want this box on the main page, so I was going to create another table just below the table with all the content to keep these two things in. I just can't make it happen on only the main page. Let me know if that makes sense, and I welcome any suggestions you have. Thanks.

Unfortunately, the homepage shares a name with category listing and product listing pages.
The changes you are discussing are major enough that you may need to make alternate versions of some parts of the file, and choose which part executes by the $this_is_home_page test.

You would also use this test in the blank sidebox file to decide whether it displays (homepage or not).

Some of the styling should be able to be done in the stylesheet, using an index_home.css stylesheet.

Actually, it is possible that all the changes you want can be done in index_home.css, along with the blank sidebox edit. We would need to see your site and a mockup of what you want to give better advice.