Let's unpack the motherboard and the computer chip and marry them together as a single unit. First, we'll get set up to work. Fold a towel that will not generate a lot of static electricity, i.e. an older towel, and place that where your going to place the motherboard after you take it out of the packaging. An old plastic cafeteria tray underneath the towel is ideal. Do not use a metal baking tray. The purpose of the tray is to be able to slide the motherboard around easily without picking it up, and the purpose of the towel is to give you a little cushion as your plugging the fan and memory into the motherboard. Be careful not to bunch the towel as you don't want an uneven surface when your plugging in components which could bend the board.
Remove the motherboard from its packaging. Do not take it out of the antistatic bag yet. With the motherboard may be an instruction booklet, a cd with some software on it, and some wiring, depending on the motherboard manufacturer. There will also be a thin aluminum panel with holes in it. Be careful with this, as it bends easily. Put everything, but the motherboard, aside for now. Ground yourself from static electricity by touching a something metal like a metal electrical outlet cover, or although at this point not the best, the computer case will work. Take the motherboard out of the antistatic bag and place it on the towel.
Remove the Intel Core 2 Duo from its packaging. You will find a computer chip and a CPU fan. Put the fan aside for now. When handling the computer chip handle it by the sides of the board it is on. Do not touch the pins. Put the chip down by the motherboard for now.
Looking at the motherboard, you'll find a square with a gray plastic cover on it. This is the LGA 775 socket where the chip will plug into the motherboard. The socket has a latch on the side that is held in place by an outcropping on the motherboard. Press the latch down and then out and it should pop up. Once the latch is up you can lift the metal hinged cover over the socket, which will fold up like the page of a book. The metal covers purpose is to apply uniform pressure to the chip.
Lift up the plastic socket cover, and remove it completely from the socket and motherboard. Do not touch the socket pins. You want to save the socket cover in case you have to return the motherboard back to the manufacturer. They require you to have the cover in place when shipping. Just put it aside for now.
Your now looking at the LGA 775 socket. The socket consists of a bunch of pins sticking up in the air and flattened out at the top. It looks like they're flat against the back of the socket, but there not. You do not want to push the chip down on top of the socket. If you do, you could bend a pin and loose a contact point, or worse, end up with a pin touching another pin. Inserting the computer chip into the socket should mean no pressure on your part. Were going to let the cover do the work.
The socket has plastic outcroppings and the computer chip has notches that only allow you to place the chip in the socket one way. They're keyed. Handling the chip by the edge of the card, gently place the chip in the socket in the correct position. Do not move the chip back and forth, or push down on the chip. The cover will apply the pressure. Just place the chip gently on top of the socket.
Swing the cover down so it covers the chip, bring the lever down so it catches the end of the cover, and swing it underneath its anchor so it stays down in place. Congratulations, you have just mounted the Intel Core 2 Duo to your motherboard. All is well in life.