To use the style you must first install its 3 parts.. "template", "style", "images", then install the style as a whole. After which you can use the style by either allowing users to change their styles or by setting the style as the forums default style.
You can change the colors of the forum style by editing the corresponding css files usually "colours.css"
also there may be a bit in "common.css". To adjust your logo you can edit "common.css" I believe.
Although the logo could be hard coded into the overall_header.html file. In which case you would need to edit it there.
Its been awhile since i've looked at the files for phpbb.
Keep in mind that any changes made to the hard files won't be picked up unless you have "stale style componets" checked in the ACP. Or unless you refresh the database with the changes made.
You are using the eTech style. It is a subsilver2-based style. In order to change some of the style's colors, you're going to need to edit a CSS file. The file is located here: styles/etech/theme/stylesheet.css and you can edit the CSS in that file to change the colors of your style to what you wish.
well filezilla is neither of those.. Filezilla is a third party FTP software...
So Judging by that I assume that your editing the hard files.. aka the files on the server.
When you edit those files you need to either go into the ACP go to the STYLE tab and update the files to the database after each change. Or you simply need to check the option "Recompile Stale Style Components".
I'm not sure where exactly that is in the ACP. So you'll just have to look for it. I believe its in the "Board Preferences" section but again I'm not sure.