A website runs based on two themes. One is for admin panel and another one is for website front end. Generally we configure and change website theme from following menu in admin panel:

Preference > Theme

Activate and Remove   Theme:

In template section you will see a "Theme Collection" area with a list of all installed templates. Click on "Install" link to activate the theme. The remove link is use to delete full theme source from server.

Theme Setting:

Theme setting parameters depend on Theme Creator inputs. Generally we find the options in left side menu under "Theme" tab. Common setting parameters are about Logo, Member Options, Banners etc.

Edit Theme CSS:

Click on "Theme Css" link on left side to update  default CSS file. Also click on "Browse Directory" button on top right of the editor to see more css links.

Edit Header, Footer:

Click on left side Header and Footer links to edit html.

Use appEditor sanction for more advanced edit like Element, View, Controller, Model. The appeditor contain minimum options to edit files. But we recommend to use Code Editor(Like Notepad++, Editplus, Comodo etc) to edit code and upload by FTP client.