Magento

I have a magentoshop which I want to modify, I have succeed to download the front site with software called Kompozer; afterwards iv manged to change the html files that needed changes. But when even I try to upload the modified site nothings happens ( I simple cant locate my html files) . I have also tried to do the same with dreamweaver and with the same disappointing result.  My question to you guys is where do I locate the html files and how do I make changes to them ? I have also managed to download the entire site to view look but to no avail.
Please help me out,!

PHTML files of base layout are located here: \app\design\frontend\base\default\template. But I strongly recommend not to edit anything in this folder, but rather create a new theme with all edits you need. A tutorial on theme creation can be found here: http://www.magentocommerce.com/design_guide

Thank you for the response its very much appreciated, as advised I have hired a freelancer which will do the job, thanks again.

it must place the file permanently in the folder called “uploads”. the reason i say permanent, i read in the tutorials that it will get placed in a temporary location and then get moved? i just want the file to be uploaded to the folder, plain and simple.