How does one set up the margins for a document (e.g., 2" on top, 1" on sides,1/2" on bottom)?

First, the answer depend on whether you have a Mac, Unix, or Windows system. Then it depends on what exactly you mean by "document", and what program you are using to make it. Every program you use has a tools menu. If you use tools a lot it will be a toolbar across the top of the screen. If you rarely use tools it might be hidden. In Windows you can click "Start" and select "Control Panel" and that gives you a menu of menus to control everything the computer does. You can right click anything and most of the time get a menu for that specific item. For example if you right click the desktop you have the option to rotate the monitor image in some graphic cards. That allows you to have an image that is high instead of wide, by turning your monitor. You don't need to memorize all these things, just be aware that they are in there. Then you can claim to know how to operate a computer at the beginner level.

In many programs you can click the "File" button at the top of the screen and select "Page Setup" but not all programs work that way.