What do you mean when you say tabs, since I doubt you mean something like this? To set up paragraphs in html you'd usually use the <p> element, but whether that's what you're looking for depends entirely on what exactly you want to accomplish.
If you just want specific elements/new paragraphs to have indents you could work with the text-indent property.
Hard to see inbetween what? Every seperate <p> or <div> should have a gap between them. You can insert breaks using <br> or use the CSS white-space property to set up how white space is handled.