What is a good free FTP client I can download? - FileZilla: it's easy to setup and use.

 I logged in using FTP, what folder do I upload my site to?

Any content you want to be publicly viewable, just upload it to your "public_html" folder.

 I uploaded a file or script and it doesn't seem to work.

Some files require special permissions or may need to be specifically uploaded in either ASCII or...