Re: How to view source code
If I understand your question correctly, what you need to do is edit the templates (for page layout) and/or php files (for page functionality) that are used to produce Tiki's pages. What specifically do you want to do? Knowing that would make it easier to point you in the direction of a particular file. For example, tiki-top_bar.tpl is in the templates directory of your Tiki installation and can be edited and then uploaded via ftp if you want to add a graphic or make other changes to that part of the page. Is this the kind of thing you're asking about?
-- Gary