Not sure what you are trying to do, if you like a template from a free site you get the whole thing as a zip file, extract it and upload the contents to your hosting site through filezilla, filezilla wont change the layout or any part of the website. In there there should be a file called index.html, thats your frontpage, edit that using a txt editor such as notepad++.
If the site spans a browser or stays at a fixed size will depend on how the site was written and what sizes were set in the html.