This is a free lesson from The Computer Manual, if you are interested in a computer basics manual, and or tutorials, visit the TheComputerManual.com to see the contents and pricing of the book and the video tutorials.
Out of the box you should be able to put the computer together. All of them come with a quick guide, so you should follow that guide.
The computer needs a monitor, that is your visual interface, a keyboard, a mouse, and audio speakers and you should be set. Other peripherals can be added as needed.
#1 VGA it connects to the monitor, note the blue color.
#2 DVI all of them are connectors that go to the monitor, the plastic is usually white
#3 PS2 connections Keyboard (purple)
#4 PS2 Connections Mouse (Green)
#5 USB (Universal Serial Bus) almost all peripherals connect to USB.
#6 LAN, Ethernet, or Network connection
#7 Audio out, the green coded connector goes to your speakers.
#8 HDMI Port (High Definition Multimedia Interface) it connects to TVs, Sound systems and monitors