HTML Editor?

I am able to log into my server just fine, but I would like to know how I can edit and SAVE my style sheets using this system? I can view my folders, but I'm not sure how to access the html files within them.
In other words...change my html and save it so that my website reflects those changes.
Thanks for any help..it's greatly appreciated.

Mike

download -> edit with your favorite editor -> reupload