1. To capture your entire screen..
- ⌘ cmd (Apple key) + shift + 3, and you should hear a camera capturing sound. Look on your desktop and you will see the picture file there..
2. To capture only a portion or section of your screen
- ⌘ cmd (Apple key) + shift + 4. the cursor will change to +. Drag the + around the section you want to capture.. Again look on your desktop and you will see the picture file there..
3. To capture a active window
- ⌘ cmd (Apple key) + shift + 4. the cursor will change to +. Press the space bar once and the + cursor will change to a camera icon. Now select the active window you want to capture. Look on your desktop for the picture file.