THE LEFT MOUSE BUTTON
1) You normally almost always use the left mouse button to select something, either with a single-click or a double-click.
2) You almost always double-click on "icons," which look like little cartoons, and single-click on buttons, which look like the keys on your keyboard; i.e., they have a 3D appearance and are usually gray.
THE RIGHT MOUSE BUTTON
1) The right mouse button is used to bring up a special menu pad that is different depending on where you click. The menu pad has only those commands on it that are applicable for that particular situation or place where you click.
For example, if you right-click on the "desktop" somewhere, this will bring up a menu pad with commands on it having to do with changing the color of the desktop or the arrangement of the icons on your desktop.
CENTER "WHEEL" BUTTON
1) Some mice have a center button that you can roll with your pointing finger. This button is used to scroll up and down on a long document or web page.
2) You can also usually "click" it to place an icon that looks like a compass "rose" (showing north, south, east and west) on the page where the cursor is or in the vertical scroll bar at the right-hand side of the screen. The mouse pointer will then change to a different kind of arrow.
3) If you then move the new mouse pointer up above the rose, the page will scroll up. If you move the mouse pointer down below the rose, the page will scroll down. (This usually works in the horizontal direction, too.)
4) The farther away you move the mouse pointer from the rose, the faster the page will scroll. You can even remove your hand from the mouse and the page will scroll up or down automatically for you.
5) To get rid of the rose, just "click" the wheel button again. You can then roll the wheel with your pointing finger again to scroll up and down on the page.