Custom template for homepage– help please!!

I am new to wordpress and php, but do have enough css and html skills to make a (horrible) website. However, I am loving WordPress and need some guidance understanding how to tweak themes, pages etc.

As I am creating a website for my computer repair/I.T. business, I want a static home page with no sidebar. I have a theme installed that I hope to be able to customize to my preferences, adding a logo, changing the banner image- basic stuff that I believe is all easy to change (right?).

I would also like a scrolling banner on my homepage to rotate through different services– this is just a plug-in and will work with any theme, right?

I have successfully removed the sidebar by following another post– I made a duplicate of page.php and saved it as homepage.php, adding the template header and removing the reference to get_sidebar.

This has worked, and the sidebar is gone…but now I need to make the content width 100%. I have examined the php file and cross-referenced them with style.css for classes defining a width of anything but 100% and have had no luck.

What am I doing wrong?

Thanks for reading, peeps.