After removing the motherboard, flip it, right hand over left, to reveal the heatsink.

When the motherboard is laying on the table, the wireless card slot should be on the top left corner of the motherboard.

On the right should be the various USB and plug in ports.

The heatsink is easily identifiable by the copper band that stretches across the back of the motherboard.

Using a Phillips #0 Screwdriver take out the four screws holding in the heatsink.