Adding a Slider with Left and Right Arrows
Design and Skin Customization
depends on how you like to develop. If you're using the "Site Builder" system, it has an image rotator (no arrows though) that cycles through the images with a number picker on the bottom.
I get the feeling you're wanting to jump sections of HTML code rather than images though.
If that's the case the steps I'd take would be to locate an example of what you're wanting to do and copy it. It's probably done with a jQuery library anyhow, so once you locate the example then you can figure out what library is being used then follow its docs. Would be the first steps I'd think to take.