You'll find information relevant to html formatting and customization here. Note that we've added features that allow more fine-grained control of css, using the html.style property and <Style> element which you could use to specify in-line css.
Since the display is html/css based, you do need to have a good understanding of these technologies and their interactions.
Taking Tabbed Pane as an example, width should be specified using an html.width property, but since this display is ultimately created using a combination of tags (mostly divs containing divs and other tags), its width will be determined by the interaction (as it were) of all contained tags.
Simple Table is actually meant to be used as is with minimal formatting (unless you're willing to override the default styles defined by our client for this template - see the link above for links to more details).
Regarding Get/Set Style Attribute, both expect the name of the css attribute through the <Attribute> trigger (usually you would use a text constant to define this), and a reference to the display element on which to apply this via the <Element> trigger (use an ancestor reference to get the reference to the element).
I hope this provides some food for thought, and please post any followup questions or problems.
Sorry for the belated response & regards,
For best results, use the Firefox browser..