Customize my site

I have been learning some css and html.  I want to apply some css, google fonts and jquery to my boonex site and keep those changes.  

What is the best approach to changing the css and keeping the changes?

I want control of background and adding my own icons is this possible?

Thanks!

Yes, it is possible.  I suggest that you actually add the fonts to your server instead of linking to Google; who knows what Google might do.  Of course there are sources for web ready fonts than just Google.  By the way, it appears that Google's new motto  is "Be as evil as possible."

For the CSS, you want to copy the template into a new name; tutorials are here on the forums.  Then you can apply that new template as your default template and make changes to the CSS.  That way, an upgrade won't overwrite your CSS changes.

As for jquery; your files won't get over written by any upgrades unless you are adding different versions of files already provided by Dolphin.  That could get tricky.