Help expanding my website

Hi my name is Shane and Im currently trying my hand at Yii development after limited experience with PHP and CSS, I am primarily an art student, majoring in animation and design but have worked with many programming languages in the past and am thoroughly computer literate.

My website is ((

(NOTE: My sqlite database works locally, but I have yet to get it going on the web server.)

login: user password: user (Cant see most content and tabs without logging in)

An online reference and blog for the animation industry, I plan to keep details for each individual animator, animation and studio along with users on the database.

I have a strong sql database all linked through relationships however from this point I am unsure how to expand the site. I wish to add a blog, registration system and a distinct layout to the site.

I am aware of the Blog tutorials however, I am unsure how to apply this to an existing site? How do I add new content without destroying what I already have?

The same goes for the Registration system how do I add this without hurting the regular login system.

Also I dont quite undertand how to dynamically edit the layout, I have found the css files but editting these doesnt quite change things up in the manner that I wish; think original layout with banner, and other imagery.

Sorry, again I am primarily an art student so it would help alot if someone could walk me through a few of these things.