Unless you have never used a computer before, you are probably at least somewhat familiar with the basics of getting around a computer with the mouse and keyboard. Haiku is very much like other computer software in that it uses files and folders, but it also has a few other tricks up its sleeve which make working a little easier, provided that you know about them.
Folders and Files
Files are documents that you -- or someone else -- make and save for later use, obviously. Folders are containers used to organize them, but you knew that already.
Links to Files
Macintosh computers call them 'aliases' and Windows calls them 'shortcuts'. Regardless of what you want to call them, Haiku allows you to make an icon which pretends to be another file when you double click on it. This is really useful on the Desktop for programs or other documents you use quite a bit.
Something which may strike you as unfamiliar is the concept of Volumes. A volume is a disk or a section of a disk. In order for Haiku to use a disk, such as a floppy you just put in the drive or that fancy new flash drive that doubles as your keychain, you need to do something called 'mounting' it. This is merely telling Haiku that you want it to make the drive available for use. Any volumes that Haiku has available for use will appear on the Desktop. If you have lots of them, you may wish to unmount volumes which you don't use to make the others easier to find.
A technology unique to Haiku and its BeOS brethren are queries. Queries are a way of quickly finding files or folders based on what you know about them, such as what kind of file it is. You can save them and use them later, create music playlists out of them, check your e-mail with them and do many other things. They are very powerful and have been copied by MacOS X and Windows Vista. More on this later.
The Desktop 
The Desktop is a workspace for you to place folders, files, and links to give you quick access to them. You can also add a picture to act as the background to show your own unique personality.
The Deskbar 
The Deskbar is quite a lot like the Start Menu used in Windows, but it has some differences that make it stand out as being an easier way to work. The main functions of the Deskbar are allowing you to open applications and preference panels, to manage windows, as an easily accessible way of opening recently used documents and applications, to search for files and to shut down or restart your computer.
The Deskbar consists of three major parts, the menu (which is accessed by clicking the leaf), the status view (which consists of the clock and system information), and the window list, which is as the name describes: a list of all your currently open applications and their windows. Clicking on the blue leaf will open up a menu which will allow the user to select programs.
In its default position the menu is located in the top right corner, but can be moved by grabbing the dotted line to the right of the status view with the mouse and dragging it to the desired location. Pulling the Deskbar to the center of one of the top or bottom of the screen will give you the standard "Windows" look. Pushing it towards a corner can also give you a condensed "mini" menu. Configuring the Deskbar is also quite easy. Click on the "leaf", mouse over "Deskbar Settings" and click on "Configure Leaf Menu". From here you can add/ remove programs or groups from the Deskbar menu. You can also change preferences like how many recent apps or documents you want listed here.
Opening applications 
Opening an application with the deskbar is easy. Simply select the menu, move the cursor down to the text reading "Applications" and a list of the available applications will appear, allowing you select the one you want by clicking on it. The process for opening preferences is nearly identical, the only exception being that "Preferences" should be selected instead of "Applications".
Managing windows 
To draw focus on a window, simply click the open application's entry in the window list. If the application has multiple windows open, you can select which one by clicking and holding the mouse button on the application's entry. This also presents you with the options of showing/hiding/closing all of that application's windows or quitting the application. Another handy feature of the window list is the ability to open files by dragging them onto an application's entry. An example of this would be opening a text file by dragging it from a Tracker window onto a running "StyledEdit"'s window list entry.
Accessing recently opened documents or applications 
Accessing recently opened documents or applications is performed in much of the same fashion as opening applications or preferences. Simply select the menu, select either "Recent Applications" or "Recent Documents", then select the entry you desire.
Searching for files 
Searching for files is simply a matter of accessing the menu, selecting "Find...", then in the window that appears, entering what you are looking for in the text box and clicking "Search". A Tracker window will then appear with the search's results. For a more in-depth look at searching for files on Haiku, see the section "Finding Files and Folders: Queries".
Shutting down or restarting the computer 
To shut down or restart your computer in Haiku, just select either "Shut down" or "Restart" from the menu.
The Tracker 
Tracker is the part of Haiku which allows you to manage your files. If you are familiar with the Finder on a Macintosh computer, then you will find Tracker to be quite familiar. Anyone familiar with Windows should find no problem in using Tracker. In fact, you may find it easier to use.