Some questions

So I have been looking at some sites like: Webdesignerwall and Ndesign Studio. Now i am new to WordPress, But not new to HTML and CSS. I understand how to styalize and create themes. But what I dont get is how to make it so you only see a fraction of whats in the post and clicking on the post title takes you to the main post it’s self.

I tried: Settings -> reading -> Summary but that didnt work. i still see the whole blog post when I only want to see a bit of it.

Also if you notice on those sites there nav has a Home tab, how would I create that in the Admin section? or is that something I have to do with one of the PHP files?

Also If I put something like Lightbox in my theme or thick box or any thing Jquery/ajax does it go in the theme folder? and is there anything special i have to do in the PHP files to make sure it still activates?

Can i add my own personal style with CSS and HTML to each page i create via the admin section? if So where are these files, such as About? How do I style them? (by style I mean set up the way images are displayed – or is this already done when i created the theme it’s self?)

Thank you for your help.