I am trying to change some buttons, but i can not find where are HTML FILES to changes.

Koha uses templates in conjunction with Perl scripts instead of HTML files. It is not recommended that you make changes to the templates. Instead, users are encouraged to use custom CSS and custom JavaScript to make interface changes. If you tell us what buttons you want to change and how, we can give you some suggestions. -- Owen -- Web Developer Athens County Public Libraries http://www.myacpl.org