Template customization
Simple alterations of a template can be done fairly easily by poking around in transform.xsl
Before you start tinkering with the template's transform.xsl you should make a backup of it so you can restore it if your modifications cause webgeno to fail. Open transform.xsl in a text editor and see if you can make any sense of it. If you're not experienced with XSL, I suggest you limit yourself to some simple additions or deletions of things that you think appropriate.
Do you have to keep the "generated by webgeno" notice? No, but it would help webgeno to get the word out about webgeno.
Note that if you use one of the www.freecsstemplates.org templates, you need to keep the copyright notice with the link back to their website.