Hello

What do you mean with "header"? Do you want to change the design of the page header? Please provide more information.

I would like to place a logo while adding links on this header. A bit like this:

Is what I can modify data from the application already installed on my server and I need to change the application first before installing?

And if I can do it directly on my server, which file I need to change and in what language?

There is a directory named themes/default wich contains some *.tpl files. You have to change the main.tpl where you have to put an <img>-Element into the <div id="top">. Alternatively you can set the image as background in the file style.min.css in the same directory (what I would strongly prefer). There you have to search for #top to edit the matching CSS-rule. In both cases you should be able to handle the languages HTML and CSS to know what you are doing.

Tschö, Auge