Theme Editor?

i am a complete noob to wp, and i as wondering where the heck i am supposed to edit the templates? on the dashboard there is the “theme editor” with the words “If this file were writable you could edit it.” on the bottom. ????

i can type on the templates, but there is no “save” or “rebuild” option. i am assuming i would copy the templates into dreamweaver and then start a new theme, afterwards uploading it with my ftp and then the theme would show up in the “theme editor”? i am wondering if minor changes to the CSS and what not cannot be made on the dashboard? or does all editing need to take place outside wp and uploaded?

i have been exploring the tutorials and there are excellent ideas for changing things, but i am wondering where the i start? in the theme editor or elsewhere?

thanks,

t