Changing Layout of a Product Page
I am new to Drupal and Drupal Commerce but I am familiar with HTML and CSS concepts and a tiny bit pf PHP expererience. I'm just developing a website on Drupal Commerce - what I've got so far can be found here: http://www.rivierabmw.com
I would like to change the layout of the product screens. Currently it is like this, with all my text and fields going down the right hand side: http://www.rivierabmw.com/en/productdisplay/bmw-e46-m3-2-disques-ventil%...
I would like to set this up so some of my fields are on the right hand side but where the 'body' of my content (the product description) goes in the centre of the page.
I'd also like to change the picture thumbnails to be underneath the main image rather than to the left side.
However, I can't find out what actually controls the positioning of these things. Is it controlled by Views, Themes (CSS) or something else entirely?
Thanks in advance for your help!