css content position fixes

I've created a website using a full screen and supersize java template, having reverse engineered one of the example sites from the person who sold the template. I've been trying to customise it, and can get the rudimentary elements working (the slideshows backgrounds, the sliding backgrounds, the navigation etc) However i want to customise how the content appears on each page. I simply want to centre images/iframes with vimeo video etc on each page, but cannot work out how to do it (I'm a video director with very basic web skills) I simply need someone to help fix the exisiting css or create new css id's to position the page content where i want it. you can see a working test here: [login to view URL] specifically i'd like the video on the 'play' page to be auto centred in the middle of the screen. Also the tables containing the images on hte 'around the world' page. And from these fixes i'd like to then be able myself to add similar content on the other two pages and add more links as and when required using the fixed css codes you supply. There's some conflicting css happening somewhere that is preventing me from working out how to do it, so i need some help.